Multiplying by Five

Examples

• 7 × 5 becomes 7 × 10 = 70, then half is 35.
• 18 × 5 becomes 18 × 10 = 180, then half is 90.

Quiz: Multiplying by Five (Age 10)

1. 1

   To multiply a number by 5, what should you do?

   • Take half of the number, then multiply by 5.
   • Multiply by 10, then add 5 to that answer.
   • Multiply by 10, then take half of that answer.
2. 2

   When you multiply a number by 10, what happens?

   • A zero is added to the number.
   • The number stays the same.
   • The number is cut in half.
3. 3

   If ten groups make 80, how many do five groups make?

   • 85, because you add 5 to 80.
   • 70, because you subtract 10 from 80.
   • 40, because half of 80 is 40.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.