Subtract 9 in Your Head

Examples

• You have 52 grapes and give away 9. Think 52 - 10 = 42, then 42 + 1 = 43.
• You have 34 stickers and give away 9. Think 34 - 10 = 24, then 24 + 1 = 25.

Quiz: Subtract 9 in Your Head (Age 8)

1. 1

   Which is a quick way to subtract 9 from a number?

   • Take away 10, then take away 1 more.
   • Take away 9, then add 10.
   • Take away 10, then add 1.
2. 2

   You subtract 10 from a number. How does the answer for subtracting 9 compare?

   • It is 1 more than the answer for subtracting 10.
   • It is the same as the answer for subtracting 10.
   • It is 1 less than the answer for subtracting 10.
3. 3

   Why do you add 1 back after taking away 10 to subtract 9?

   • Because you took away one too many.
   • Because you want to add back 10.
   • Because you want to take away 1 more.

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.