This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using multiplication and subtraction to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. In this problem, Ava has $60 and buys 7 notebooks for $8 each, and we need to find how much money is left. This requires multiplication to find the total cost, then subtraction to find what's left. Choice A is correct because Step 1: $7 \times 8 = 56$ spent on notebooks. Step 2: $60 - 56 = 4$ left. Equation: $m = 60 - 7 \times 8 = 4$. This answer is reasonable because 7 notebooks at about $8 each costs about $56, leaving about $4 from $60. Choice B ($52) is incorrect because it subtracts only $8 from $60 (60-8=52), showing the student only accounted for one notebook instead of 7. This error occurs when students don't multiply to find the total cost. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns. Practice estimation BEFORE solving: "$7 \times 8$ is about $56$" helps catch errors. Check reasonableness: "Does having $52 left after buying 7 notebooks make sense? No!" Use visual models to show buying multiple items. Emphasize that "7 notebooks for $8 each" means multiply, not just subtract $8 once.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using subtraction and division to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. In this problem, Grace picks 64 apples, gives away 16, then packs the rest equally into 8 bags. This requires subtraction to find remaining apples, then division to find apples per bag. Choice B is correct because Step 1: 64-16=48 apples remaining. Step 2: 48÷8=6 apples per bag. Equation: a=(64-16)÷8=6. This answer is reasonable because about 48 apples in 8 bags gives 6 per bag. Choice C (8) is incorrect because it divides the original 64 by 8 (64÷8=8), ignoring that 16 apples were given away first. This error occurs when students skip the subtraction step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Emphasize chronological order: apples are given away BEFORE packing. Use visual models showing removing 16 from 64 before dividing. Model with parentheses: (64-16)÷8. Watch for students who use all numbers without considering what happens to them.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using subtraction and division to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: 'Had 24 stickers, bought 3 packs of 8, how many now?' Step 1: Find stickers bought: 3×8=24. Step 2: Add to original: 24+24=48. Equation: 24+3×8=s or s=24+3×8. Check: About 20+30=50, so 48 is reasonable. In this problem, the library has 72 books, 18 checked out, rest placed equally on 9 shelves, asking how many per shelf, which requires first subtraction to find remaining, then division by shelves. Choice B is correct because Step 1: 72-18=54 remaining. Step 2: 54÷9=6 per shelf. Equation: b=(72-18)÷9=6. This answer is reasonable because about 70-20=50 in 10 shelves is 5, but 9 shelves make about 6. Choice D is incorrect because it subtracts but doesn't divide (72-18=54). This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: 'About 50÷10=5' helps catch errors. Check reasonableness: 'Does 54 per shelf make sense for 9 shelves? Too many!' Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—(12+8)÷4 ≠ 12+8÷4. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using addition and multiplication to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: "Had 24 stickers, bought 3 packs of 8, how many now?" Step 1: Find stickers bought: 3×8=24. Step 2: Add to original: 24+24=48. Equation: 24+3×8=s or s=24+3×8. Check: About 20+30=50, so 48 is reasonable. In this problem, Noah has 7 red and 5 blue marbles, with green being 3 times as many as red and blue together, asking how many green. This requires addition to find red and blue total, then multiplication for green. Choice A is correct because Step 1: 7+5=12 red and blue. Step 2: 3×12=36 green. Equation: s=3×(7+5)=36. This answer is reasonable because about 10 total red/blue times 3 is 30, so 36 makes sense. Choice D is incorrect because it adds red and blue (12) without multiplying by 3. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: "About 20+30=50" helps catch errors. Check reasonableness: "Does 847 stickers make sense from buying 3 packs? No!" Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—(12+8)÷4 ≠ 12+8÷4. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using addition and division to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: 'Had 24 stickers, bought 3 packs of 8, how many now?' Step 1: Find stickers bought: 3×8=24. Step 2: Add to original: 24+24=48. Equation: 24+3×8=s or s=24+3×8. Check: About 20+30=50, so 48 is reasonable. In this problem, Jada collects 9 and 15 shells over two days and makes 4 equal groups, asking how many per group, which requires first addition to find total, then division by groups. Choice B is correct because Step 1: 9+15=24 total. Step 2: 24÷4=6 per group. Equation: s=(9+15)÷4=6. This answer is reasonable because about 10+15=25 in 5 groups is 5, but 4 groups make about 6. Choice A is incorrect because it only adds (9+15=24) without dividing by 4. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: 'About 25÷5=5' helps catch errors. Check reasonableness: 'Does 24 per group make sense for 4 groups? Too many!' Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—(12+8)÷4 ≠ 12+8÷4. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using multiplication and addition to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. In this problem, there are 8 tables with 4 students each, then 7 more students join. This requires multiplication to find initial students, then addition to include new students. Choice A is correct because Step 1: 8×4=32 students initially. Step 2: 32+7=39 students total. Equation: s=8×4+7=39. This answer is reasonable because 8 tables of 4 gives about 32, plus 7 more makes about 40. Choice B (32) is incorrect because it only calculates the initial students (8×4=32) and doesn't add the 7 new students who joined. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Emphasize time sequence: "then 7 more join" means add to the initial count. Model with diagrams showing tables, then new students arriving. Practice identifying all parts of the problem that affect the final answer. Use clear equation notation: s=8×4+7.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using division and addition to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. In this problem, 48 cookies are shared equally into 8 bags, then 2 more cookies are added to each bag. This requires division to find initial cookies per bag, then addition to find the new amount. Choice A is correct because Step 1: 48÷8=6 cookies per bag initially. Step 2: 6+2=8 cookies per bag after adding 2 more. Equation: c=48÷8+2=8. This answer is reasonable because starting with 6 per bag and adding 2 gives 8 per bag. Choice B (10) is incorrect because it appears to add 2 to the total 48 first (48+2=50) then divide by 8, misunderstanding that 2 cookies are added to EACH bag, not to the total. This error occurs when students don't understand "each" in word problems. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Emphasize key words: "2 more cookies to EACH bag" means add 2 to the per-bag amount, not the total. Use visual models showing 8 bags, each getting 2 more. Practice order of operations: 48÷8+2 means divide first, then add.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using multiplication and addition to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: "Had 24 stickers, bought 3 packs of 8, how many now?" Step 1: Find stickers bought: 3×8=24. Step 2: Add to original: 24+24=48. Equation: 24+3×8=s or s=24+3×8. Check: About 20+30=50, so 48 is reasonable. In this problem, Maya starts with 18 pencils and buys 4 packs of 6 each, asking for the total pencils. This requires multiplication to find the new pencils, then addition to find the total. Choice A is correct because Step 1: 4×6=24 pencils bought. Step 2: 18 original + 24 new = 42 total. Equation: s=18+4×6=42. This answer is reasonable because buying 4 small packs gives about 20-25 pencils, plus original 18 makes about 40, so 42 makes sense. Choice B is incorrect because it only completes step 1 (4×6=24) and doesn't add the original 18. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: "About 20+30=50" helps catch errors. Check reasonableness: "Does 847 stickers make sense from buying 3 packs? No!" Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—(12+8)÷4 ≠ 12+8÷4. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using addition and division to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: 'Had 24 stickers, bought 3 packs of 8, how many now?' Step 1: Find stickers bought: $3 \times 8 = 24$. Step 2: Add to original: $24 + 24 = 48$. Equation: $24 + 3 \times 8 = s$ or $s = 24 + 3 \times 8$. Check: About $20 + 30 = 50$, so 48 is reasonable. In this problem, Mia picks 14 and 10 apples over two days and puts them equally into 6 bags, asking how many per bag, which requires first addition to find total, then division by bags. Choice A is correct because Step 1: $14 + 10 = 24$ total. Step 2: $24 \div 6 = 4$ per bag. Equation: $a = (14 + 10) \div 6 = 4$. This answer is reasonable because about $15 + 10 = 25$ apples in 5 bags would be 5 each, but 6 bags make about 4. Choice B is incorrect because it only adds ($14 + 10 = 24$) without dividing by 6. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: 'About $25 \div 5 = 5$' helps catch errors. Check reasonableness: 'Does 24 per bag make sense for 6 bags? Too many!' Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—$ (12 + 8) \div 4 \neq 12 + 8 \div 4 $. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.

This question tests solving two-step word problems using multiple operations (CCSS.3.OA.8), specifically using addition and division to solve a problem, representing it with an equation, and checking reasonableness. Two-step problems require two operations to solve—you can't find the answer in just one step. Strategy: (1) Read carefully and identify what you know and what you need to find. (2) Determine which operations are needed and in what order. (3) Do step 1, then use that result in step 2. (4) Write an equation using a letter for the unknown (like n, x, or s). (5) Check if answer is reasonable using estimation. Example: "Had 24 stickers, bought 3 packs of 8, how many now?" Step 1: Find stickers bought: 3×8=24. Step 2: Add to original: 24+24=48. Equation: 24+3×8=s or s=24+3×8. Check: About 20+30=50, so 48 is reasonable. In this problem, a class earns 28 points Monday and 20 Tuesday, sharing total equally among 6 teams, asking points per team. This requires addition to find total points, then division per team. Choice A is correct because Step 1: 28+20=48 total. Step 2: 48÷6=8 per team. Equation: s=(28+20)÷6=8. This answer is reasonable because about 30+20=50 divided by 5 is 10, but 6 teams make about 8, so 8 makes sense. Choice C is incorrect because it adds to 48 but doesn't divide by 6. This error occurs when students stop after one step. To help students solve two-step problems: Teach systematic approach: read, identify knowns/unknowns, plan operations, solve step-by-step, check. Model writing equations with unknowns (use letters students choose). Practice estimation BEFORE solving: "About 20+30=50" helps catch errors. Check reasonableness: "Does 847 stickers make sense from buying 3 packs? No!" Use bar models or diagrams to visualize steps. Emphasize order of operations: parentheses matter—(12+8)÷4 ≠ 12+8÷4. Connect to real life: students naturally solve two-step problems (saved $5 per week for 4 weeks, spent $12, how much left?). Watch for students who add all numbers regardless of context, or who stop after one step.