Regrouping practice

Regrouping practice

Follow the steps!!

When you regroup any number, you have to do these steps IN ORDER

• FIRST: cross out the digit you are borrowing FROM and take one away from it

FIRST

cross out the number

SECOND

Write one less than that number above it

THIRD

Add TEN more to the place on the right.

You do this by just putting a ONE in front of the digit in that place.

What is the first step to regroup 45?

First, take one from the TENS place. . .

Cross out the 4

Take one away and write 3 on top.

Now give TEN to the place on the right.

You can give TEN to the next place by just putting a 1 in front of whatever is already in that spot.

Multiple Choice

Which shows the correct first step to regrouping 83?

Remember, step one is always to cross out a digit and take one away from it.

Why does this work?

If I cross out the 8, I have 7 TENS left.

But I have to put that TEN somewhere!!!

I change the TEN into 10 ONES.

I show that by putting a ONE in front of the digit in the place to the right.

Remember,

You can't ADD anything to a place, until you get it from somewhere FIRST

Multiple Choice

If I regroup the number 23, which shows the same amount?

This is equal to 23.

• 1 TEN

• 13 ONES

• First I took one away from the TENS

• Then I gave 10 to the place on the right

Do those steps over and over again!

FIRST cross out the 7

SECOND take one away and write 6 on top

THIRD put a 1 in front of the place on the right.

Repeat for the next place

FIRST cross out the 10

SECOND take one away and write 9 on top

Then. . .

THIRD put a 1 in front of the place on the right.

Multiple Choice

Which of these is equal to 638?

Multiple Choice

Which of these is equal to 300?

When you are subtracting, you must cross the number out FIRST

• Then put a 1 in front of the place on the right.

• Repeat these steps each time you need to regroup.

• (But remember - check to see if you need to regroup in each place first! :)