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Simple & Compound Interest — Easy Worksheet 2
Grade 7 · MathSheets Name: ____________________ Date: __________
Solve each problem. Write money with a $ sign and cents (like $920.00) and rates as a percent.
How to solve
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Example
Isla puts $900 in an account that earns 2% simple interest each year. How much interest does the account earn in 3 years?
Answer: $54.00
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 6% = 0.06. I = 200 × 0.06 × 2. One year earns 200 × 0.06 = 12, so 2 years earn 12 × 2 = 24. The account earns $24.00.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 6% = 0.06. I = 200 × 0.06 × 2. One year earns 200 × 0.06 = 12, so 2 years earn 12 × 2 = 24. The account earns $24.00.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Ben puts $1,100 in an account that earns 5% simple interest each year. How much interest does the account earn in 2 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 5% = 0.05. I = 400 × 0.05 × 3. One year earns 400 × 0.05 = 20, so 3 years earn 20 × 3 = 60. Add the interest to the principal: 400 + 60 = 460. There is $460.00 in the account.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 5% = 0.05. I = 400 × 0.05 × 3. One year earns 400 × 0.05 = 20, so 3 years earn 20 × 3 = 60. Add the interest to the principal: 400 + 60 = 460. There is $460.00 in the account.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Farid puts $600 in an account that earns 10% simple interest each year. How much interest does the account earn in 3 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t and solve for r: r = I ÷ (P × t). P × t = 900 × 4 = 3,600. r = 144 ÷ 3,600 = 0.04. Multiply by 100 to change the decimal to a percent: 0.04 = 4%. The rate was 4% per year.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t and solve for r: r = I ÷ (P × t). P × t = 900 × 4 = 3,600. r = 144 ÷ 3,600 = 0.04. Multiply by 100 to change the decimal to a percent: 0.04 = 4%. The rate was 4% per year.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Emma puts $600 in an account that earns 3% simple interest each year. How much interest does the account earn in 5 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 5% = 0.05. I = 1,200 × 0.05 × 3. One year earns 1,200 × 0.05 = 60, so 3 years earn 60 × 3 = 180. Add the interest to the principal: 1,200 + 180 = 1,380. There is $1380.00 in the account.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 5% = 0.05. I = 1,200 × 0.05 × 3. One year earns 1,200 × 0.05 = 60, so 3 years earn 60 × 3 = 180. Add the interest to the principal: 1,200 + 180 = 1,380. There is $1380.00 in the account.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Ben puts $800 in an account that earns 6% simple interest each year. How much interest does the account earn in 5 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t and solve for t: t = I ÷ (P × r). Write the rate as a decimal: 4% = 0.04. One year earns P × r = 500 × 0.04 = 20. t = 100 ÷ 20 = 5. The money was invested for 5 years.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t and solve for t: t = I ÷ (P × r). Write the rate as a decimal: 4% = 0.04. One year earns P × r = 500 × 0.04 = 20. t = 100 ÷ 20 = 5. The money was invested for 5 years.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Ben puts $1,000 in an account that earns 10% simple interest each year. How much interest does the account earn in 3 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 2% = 0.02. I = 400 × 0.02 × 5. One year earns 400 × 0.02 = 8, so 5 years earn 8 × 5 = 40. Add the interest to the principal: 400 + 40 = 440. Carla owes $440.00 in all.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t. Write the rate as a decimal: 2% = 0.02. I = 400 × 0.02 × 5. One year earns 400 × 0.02 = 8, so 5 years earn 8 × 5 = 40. Add the interest to the principal: 400 + 40 = 440. Carla owes $440.00 in all.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Leo puts $400 in an account that earns 3% simple interest each year. How much interest does the account earn in 3 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t and solve for r: r = I ÷ (P × t). P × t = 800 × 2 = 1,600. r = 32 ÷ 1,600 = 0.02. Multiply by 100 to change the decimal to a percent: 0.02 = 2%. The rate was 2% per year.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t and solve for r: r = I ÷ (P × t). P × t = 800 × 2 = 1,600. r = 32 ÷ 1,600 = 0.02. Multiply by 100 to change the decimal to a percent: 0.02 = 2%. The rate was 2% per year.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Hiro puts $300 in an account that earns 2% simple interest each year. How much interest does the account earn in 3 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Use I = P × r × t and solve for t: t = I ÷ (P × r). Write the rate as a decimal: 8% = 0.08. One year earns P × r = 600 × 0.08 = 48. t = 144 ÷ 48 = 3. The money was invested for 3 years.
✓ Correct!
Not quite. The answer is
💡 Use I = P × r × t and solve for t: t = I ÷ (P × r). Write the rate as a decimal: 8% = 0.08. One year earns P × r = 600 × 0.08 = 48. t = 144 ÷ 48 = 3. The money was invested for 3 years.
💡 How to solve: Simple & Compound Interest
Simple interest is I = P × r × t: the principal P, times the yearly rate r written as a decimal, times the time t in years. $800 at 5% for 3 years earns 800 × 0.05 × 3 = $120, so the total is 800 + 120 = $920.00. To find the rate or the time, divide the interest by the other two numbers: r = I ÷ (P × t) and t = I ÷ (P × r). Write months as part of a year (6 months = 0.5 year). Compound interest also earns interest on the interest: multiply by (1 + r) once for each year. $1,000 at 10% is 1,000 × 1.1 × 1.1 = $1210.00 after 2 years.
Try a similar one
Carla puts $1,100 in an account that earns 2% simple interest each year. How much interest does the account earn in 3 years?
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
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Simple & Compound Interest — Easy Worksheet 2
Solve each problem. Write money with a $ sign and cents (like $920.00) and rates as a percent.