All PSAT Math Resources
Example Questions
Example Question #1 : How To Find The Reciprocal Of A Fraction
What is the reciprocal of the following fraction: 18/27
9
-18/27
27/18
9/27
27/18
A fraction multiplied by its reciprocal will equal 1. To find the reciprocal of a fraction, switch the denominator and numerator. The reciprocal of 18/27 is 27/18.
Example Question #1 : How To Find The Lowest / Least Common Denominator
3/5 + 4/7 – 1/3 =
72/89
3/37
88/105
7/9
4/3
88/105
We need to find a common denominator to add and subtract these fractions. Let's do the addition first. The lowest common denominator of 5 and 7 is 5 * 7 = 35, so 3/5 + 4/7 = 21/35 + 20/35 = 41/35.
Now to the subtraction. The lowest common denominator of 35 and 3 is 35 * 3 = 105, so altogether, 3/5 + 4/7 – 1/3 = 41/35 – 1/3 = 123/105 – 35/105 = 88/105. This does not simplify and is therefore the correct answer.
Example Question #162 : Fractions
3/5 + 4/7 – 1/3 =
88/105
3/37
7/9
72/89
4/3
88/105
We need to find a common denominator to add and subtract these fractions. Let's do the addition first. The lowest common denominator of 5 and 7 is 5 * 7 = 35, so 3/5 + 4/7 = 21/35 + 20/35 = 41/35.
Now to the subtraction. The lowest common denominator of 35 and 3 is 35 * 3 = 105, so altogether, 3/5 + 4/7 – 1/3 = 41/35 – 1/3 = 123/105 – 35/105 = 88/105. This does not simplify and is therefore the correct answer.
Example Question #1 : How To Find The Lowest / Least Common Denominator
Example Question #1 : How To Find The Lowest / Least Common Denominator
Simplify:
First, find the common denominator of the fractions in order to add them together. Looking at the first two fractions, we can see that the common denominator is 15 because 3 times five is 15. We can now change both fractions to have a denominator of 15 so that we can add them together:
Now, find a common denominator for the remaining fractions. This can be done by listing multiples of 15 and 20 and finding the lowest common multiple:
15: 15, 30, 45, 60, 75
20: 20, 40, 60, 80
60 is the lowest common multiple, so it is our least common denominator.
Example Question #1691 : Psat Mathematics
Simplify:
Example Question #1 : How To Find A Solution To A Compound Fraction
Simplify:
Example Question #3 : How To Find A Solution To A Compound Fraction
Simplify:
Example Question #2 : How To Find A Solution To A Compound Fraction
Simplify:
None of the other responses gives the correct answer.
Example Question #1691 : Psat Mathematics
Simplify: