Problem Solving: Number Series Flashcards

What is the next number in the following series? 3, 7, 11, 15, __

Answer: 19

This is an arithmetic progression. The pattern is to add 4 to each number to get the next one. 3 + 4 = 7; 7 + 4 = 11; 11 + 4 = 15; Therefore, 15 + 4 = 19.

Find the missing number in the sequence: 4, 6, 9, 13, 18, __

Answer: 24

The pattern involves adding a progressively increasing number. First, 2 is added (4+2=6), then 3 is added (6+3=9), then 4 is added (9+4=13), then 5 is added (13+5=18). The next step is to add 6. 18 + 6 = 24.

Which number should come next in this series? 81, 27, 9, 3, __

Answer: 1

This is a geometric progression where each number is divided by 3 to get the next number in the series. 81 ÷ 3 = 27; 27 ÷ 3 = 9; 9 ÷ 3 = 3; Therefore, 3 ÷ 3 = 1.

Identify the next number in the alternating sequence: 5, 10, 8, 16, 14, __

Answer: 28

The series follows a two-step alternating pattern: multiply by 2, then subtract 2. 5 * 2 = 10; 10 - 2 = 8; 8 * 2 = 16; 16 - 2 = 14. The next operation is to multiply by 2. 14 * 2 = 28.

What number completes the following series? 2, 3, 5, 8, 13, __

Answer: 21

This is a Fibonacci-style sequence where each number is the sum of the two preceding numbers. 2 + 3 = 5; 3 + 5 = 8; 5 + 8 = 13. Therefore, the next number is 8 + 13 = 21.

Examine the following series and determine the next number: 1, 4, 9, 16, 25, __

Answer: 36

The series consists of the squares of consecutive integers. 1² = 1; 2² = 4; 3² = 9; 4² = 16; 5² = 25. The next number is the square of 6, which is 6² = 36.