AI Tutor
Imagine you have 10 boxes of crayons, and every single box has 10 crayons inside. That means you have 100 crayons in all!
If you give 4 whole boxes to your best friend, how many crayons do you still have left?
To solve this in a snap, we can look at what 100 is really made of.

100 Is 10 Tens

A multiple of 10 is any number you get when you count by tens, like 10, 20, 30, 40, and 50.
The number 100 is equal to 10 tens grouped together.
How does knowing 100 is 10 tens make subtracting big numbers feel like a simple game?

Take Away Tens

When you see 100−40100 - 40, think of it as taking away 4 tens from 10 tens.
Because 10−4=610 - 4 = 6, having 10 tens and taking away 4 tens leaves you with 6 tens, which is 60.
What if you want to find the answer by thinking about the missing part instead?