Step by step
The question
Question: 90 is 8 tens and how many ones?
90 = 8 tens □ ones
1 Show it with blocks
A ten is 10 ones stuck together.
90 is 9 tens and 0 ones.
2 Break a ten
3 Count the ones
Now there are 0 ones and 10 more ones.
That is 10 ones.
0 + 10 = 10
4 Write the number
So 90 is 8 tens and 10 ones.
90 = 8 tens 10 ones
Careful!
8 tens and 0 ones is only 80.
We must count the 10 new ones.
Careful: not 90 = 8 tens 0 ones ✗
5 Check
8 tens is 80.
80 and 10 make 90.
Yes!
It works.
80 + 10 = 90
Let's look back.
First: show it with blocks.
Then: break a ten.
Then: count the ones.
Then: write the number.
Last: check.
Answer
90 = 8 tens 10 ones