Arithmetic, geometric or neither? Find the next terms with a recursive rule

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Bo's reading log shows the list 5, 15, 25, 35. Is the list arithmetic, geometric or neither?

   • Arithmetic: + 10 on every arrow
   • Neither: the arrows change
   • Geometric: × 3 on every arrow
2. 2.

   Esme's bake-sale tally shows the list 2, 6, 18, 30. Is the list arithmetic, geometric or neither?

   • Arithmetic: + 4 on every arrow
   • Geometric: × 3 on every arrow
   • Neither: the arrows change
3. 3.

   Jun's math-club handout shows the list 81, 27, 9, 3. Is the list arithmetic, geometric or neither?

   • Neither: the arrows change
   • Arithmetic: − 54 on every arrow
   • Geometric: × 1/3 on every arrow
4. 4.

   Kira zooms in on a seed picture again and again. Its width on screen, in mm, is 2, 10, 50, 250. What is the next term?

   1250
5. 5.

   Noah's robot token jumps the same amount each turn on a number line. Its spots are 14, 9, 4, -1. What is the next term?

   -6
6. 6.

   Ren climbs a pretend number ladder. The rule is a(1) = 6, a(n) = a(n − 1) + 9. What is a(5)?

   42
7. 7.

   Tala's class shares a jar of 50 craft sticks. The rule is a(1) = 50, a(n) = a(n − 1) − 8. What is a(6)?

   10
8. 8.

   Bo reads 12 pages on day 1 of a reading challenge, then 5 more pages each day than the day before. How many pages does Bo read on day 6?

   37
9. 9.

   Jun watches a science video: a frog egg divides, so its cells double at each stage. There are 2 cells at stage 1. How many cells are there at stage 6?

   64
10. 10.

    Luz drops a play ball from shoulder height. Bounce 1 reaches 80 cm, and each bounce is 1/2 as high as the one before. How high, in cm, is bounce 4?

    10