How saving a little each month grows: simple and compound interest

Answer Key - Grade 8 Math Worksheet - Building Confidence

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

1. Read this first

   Growth table

   Year	Balance
   0	$600
   1	$630
   2	$660
   3	$690

2. 1.

   Ari reads the table for Mr. Dunn's pretend savings account. It earns simple interest and gets no deposits. What will its balance be in year 10?

   $900
3. 2.

   Jun reads the table for the class garden fund. It earns simple interest and gets no deposits. What will its balance be in year 20?

   $2,160
4. 3.

   Kira compares two pretend accounts that each start with $500 and get no deposits. One earns simple interest and the other earns compound interest. Which account earns simple interest?

   • Account B: its balance rises by a bit more than before each year
   • Both: each balance rises from year to year
   • Account A: its balance rises by the same amount each year
5. 4.

   Luz compares two pretend accounts that each start with $800 and get no deposits. One earns simple interest and the other earns compound interest. Which account earns simple interest?

   • Account A: its balance rises by a bit more than before each year
   • Neither: both balances rise from year to year
   • Account B: its balance rises by the same amount each year
6. 5.

   Milo compares two pretend accounts that each start with $1,000 and get no deposits. One earns simple interest and the other earns compound interest. Which account earns simple interest?

   • Both: each balance rises from year to year
   • Account B: its balance rises by the same amount each year
   • Account A: its balance rises by a bit more than before each year
7. 6.

   Noah compares two pretend accounts that each start with $400 and get no deposits. One earns simple interest and the other earns compound interest. Which account earns simple interest?

   • Account A: its balance rises by the same amount each year
   • Account B: its balance rises by a bit more each year
   • Neither: both balances rise from year to year
8. 7.

   Pia reads about Ms. Hale's pretend account. It holds $500 and earns 10% compound interest a year, with no deposits. What is the balance after 2 years?

   $605
9. 8.

   Ren reads about the class trip fund. It holds $200 and earns 20% compound interest a year, with no deposits. What is the balance after 2 years?

   $288
10. 9.

    Tala reads about Mr. Lane's pretend account. It holds $800 and earns 5% compound interest a year, with no deposits. What is the balance after 2 years?

    $882
11. 10.

    Zee reads about the class garden fund. It holds $300 and earns 10% compound interest a year, with no deposits. What is the balance after 2 years?

    $363