ISEE Lower Level Quantitative : How to find the missing part of a list

Study concepts, example questions & explanations for ISEE Lower Level Quantitative

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Example Questions

Example Question #1 : How To Find The Missing Part Of A List

\(\displaystyle 2,5,11,23,47, \square\)

What is the next number in the series?

Possible Answers:

\(\displaystyle 90\)

\(\displaystyle 96\)

\(\displaystyle 85\)

\(\displaystyle 95\)

\(\displaystyle 94\)

Correct answer:

\(\displaystyle 95\)

Explanation:

First, determine what the pattern is in the series. The pattern here is to multiply the previous number by 2 and then add 1. Therefore, multiply 47 by 2 (which is 94), and then add 1. The result is 95.

Example Question #2 : How To Find The Missing Part Of A List

What is the missing value of w in this sequence?

\(\displaystyle 92, 85, 78, 71, w\)

Possible Answers:

\(\displaystyle 64\)

\(\displaystyle 63\)

\(\displaystyle 65\)

\(\displaystyle 62\)

Correct answer:

\(\displaystyle 64\)

Explanation:

In this sequence, every subsequent number is 7 less than the preceding number. Given that the number that precedes w is 71, the value of w is \(\displaystyle 71-7=64\). Therefore, 64 is the correct answer. 

Example Question #3 : How To Find The Missing Part Of A List

What is the value of n in the sequence below?

\(\displaystyle 5, 10, 15, 20, n\)

Possible Answers:

\(\displaystyle 15\)

\(\displaystyle 30\)

\(\displaystyle 20\)

\(\displaystyle 25\)

Correct answer:

\(\displaystyle 25\)

Explanation:

The numbers increase by 5. Given that the number before n is 20, the value of n is \(\displaystyle 20+5=25\).

Example Question #22 : Sets

What is the next term in the following sequence?

\(\displaystyle \left \{ 4,11,18,25,32... \right \}\)

Possible Answers:

\(\displaystyle 39\)

\(\displaystyle 38\)

\(\displaystyle 37\)

\(\displaystyle 40\)

\(\displaystyle 41\)

Correct answer:

\(\displaystyle 39\)

Explanation:

What is the next term in the following sequence?

\(\displaystyle \left \{ 4,11,18,25,32... \right \}\)

This is an arithmetic sequence with a common difference of \(\displaystyle 7\). To find the next term in an arithmetic sequence, add the common difference to the previously listed term:

\(\displaystyle 32+7=39\)

Example Question #2 : How To Find The Missing Part Of A List

Find the missing number in the sequence:

\(\displaystyle 5, 8, 14,..., 50\)

Possible Answers:

\(\displaystyle 18\)

\(\displaystyle 24\)

\(\displaystyle 26\)

\(\displaystyle 28\)

\(\displaystyle 20\)

Correct answer:

\(\displaystyle 26\)

Explanation:

In this sequence, the difference between each number is double the difference between the number that came prior to it in the sequence. For example, \(\displaystyle 8-5=3\) and \(\displaystyle 14-8=6\). Thus, the missing number must be greater than \(\displaystyle 14\) by a difference of \(\displaystyle 12\) and therefore \(\displaystyle 14 + 12= 26\)

Example Question #4 : How To Find The Missing Part Of A List

What is the missing number in the following list: 

\(\displaystyle 1, 3,..., 11,17\)

Possible Answers:

\(\displaystyle 7\)

\(\displaystyle 6\)

\(\displaystyle 5\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle 7\)

Explanation:

In this sequence of numbers, there is an important pattern to recognize. In this sequence each number is a prime number, however the sequence skips every other prime number. Thus, the sequence begins with the prime number \(\displaystyle 1\) and then skips the prime number \(\displaystyle 2\) (which is the only even prime number) and goes to \(\displaystyle 3\). From \(\displaystyle 3\) the next prime number is \(\displaystyle 5\), however since the pattern in this sequence skips every other prime number--the missing number is \(\displaystyle 7\).      

Example Question #5 : How To Find The Missing Part Of A List

Find the missing number in this set:

\(\displaystyle 4, 8,...14, 16\)

Possible Answers:

\(\displaystyle 9\)

\(\displaystyle 12\)

\(\displaystyle 10\)

\(\displaystyle 13\)

Correct answer:

\(\displaystyle 10\)

Explanation:

In this sequence of numbers, there is an important pattern to recognize. Each number in this sequence is a composite number--however, the sequence skips every other composite number. Thus, the next composite number after \(\displaystyle 8\) is \(\displaystyle 9\)--which is skipped because of the pattern, making the correct answer \(\displaystyle 10\).

Example Question #23 : Sets

Find the next number in the list: 

\(\displaystyle 21, 28, 35,...\)

Possible Answers:

\(\displaystyle 42\)

\(\displaystyle 40\)

\(\displaystyle 43\)

\(\displaystyle 37\)

Correct answer:

\(\displaystyle 42\)

Explanation:

In this sequence of numbers, there is an important pattern to recognize. Each number is greater than the number prior to it by a margin of \(\displaystyle 7\). In other words, each number in this list is a multiple of \(\displaystyle 7\). Thus, \(\displaystyle 35 + 7= 42\) 

Example Question #71 : Data Analysis And Probability

Find the missing number:

\(\displaystyle 9, 13, 17, 21,..., 29\)

Possible Answers:

\(\displaystyle 25\)

\(\displaystyle 26\)

\(\displaystyle 24\)

\(\displaystyle 28\)

Correct answer:

\(\displaystyle 25\)

Explanation:

In this sequence of numbers, there is an important pattern to recognize. Each number is greater than the number prior to it by a margin of \(\displaystyle 4\). Thus, the correct answer is \(\displaystyle 25\), because \(\displaystyle 21 + 4=25\)  

Example Question #1633 : Isee Lower Level (Grades 5 6) Quantitative Reasoning

Find the missing number in the list below: 

\(\displaystyle 26,..., 44, 53, 62\)

Possible Answers:

\(\displaystyle 37\)

\(\displaystyle 29\)

\(\displaystyle 35\)

\(\displaystyle 28\)

Correct answer:

\(\displaystyle 35\)

Explanation:

In this sequence of numbers, there is an important pattern to recognize. Each number is greater than the number prior to it by a margin of 9. Thus, the correct answer is \(\displaystyle 35\) because \(\displaystyle 26 + 9 = 35\)

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