Patterns and Number Sequences — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Inputs are 2, 4, 6, 8 and outputs are 7, 9, 11, 13. What is the rule?
A) Multiply by 3
B) Add 5
C) Add 3
D) Subtract 1
When each term increases by 5, the rule is add 5.
2. What rule makes the pattern 3, 9, 27, 81?
A) Add 6
B) Add 18
C) Multiply by 3
D) Multiply by 9
Each term is multiplied by 3: 1 × 3 = 3, 3 × 3 = 9, 9 × 3 = 27.
3. In the pattern 1, 1, 2, 3, 5, 8, what comes next? Hint: add the last two numbers.
A) 10
B) 13
C) 11
D) 9
The rule is add 3. 10 + 3 = 13.
4. Starting from 2, which rule gives a larger 4th number: add 5 or multiply by 2?
A) Add 5 gives 17
B) Multiply by 2 gives 16
C) They are equal
D) Add 5 gives 20
8 × 2 = 16. Multiplying 8 by 2 gives 16.
Part B: Fill in the Blank
Write the correct answer on each line.
1. In the pattern 5, 10, 20, 40, each number doubles. The next number is 80.
The rule is multiply by 2 (doubling). 40 × 2 = 80.
2. An input-output table uses multiply by 4. If the input is 7, the output is 28.
7 × 4 = 28. Apply the rule multiply by 4 to the input 7.
3. The pattern 11, 22, 33, 44, 55 is missing the number 44.
The rule is add 11. 33 + 11 = 44.
4. In the pattern 96, 48, 24, 12, each number is divided by 2.
Each term is divided by 2: 96 ÷ 2 = 48, 48 ÷ 2 = 24, 24 ÷ 2 = 12.
5. The 9th number when counting by 6 is 54.
Counting by 6: 6, 12, 18, 24, 30, 36, 42, 48, 54. The 9th number is 54.