Subtraction Intro

Subtraction Intro

Today, we will be able to subtract using the regrouping strategy.

Multiple Choice

Which number goes on top when subtracting?

• larger number

• smaller number

• even number

• odd number

Multiple Choice

Can he give you the amount of pizza you asked for?🍕🍕

• yes

• no

Multiple Choice

We had 2 tens. We took 1 ten away. How many tens will be left?

• 0

• 1

• 2

• 3

Multiple Choice

What is 17-9?

• 6

• 7

• 8

• 9

Multiple Choice

What is 1-0?

• 0

• 1

• 2

• ice cubes

Multiple Choice

Are there enough ones to subtract? IS THERE ENOUGH PIZZA??? 🍕🍕

• yes

• no

Multiple Choice

What is 12-6?

• 5

• 6

• 7

• 8

Poll

Do you like ranch dressing?

• yes

• no

Regrouping

In this video, he talked about borrowing. That was an older term used in subtraction. A more accurate term we use today is “regrouping”. Regrouping is when we rearrange groups in place value to carry out an operation.

       Do you remember place value from last Saturday? Let’s see!

Multiple Choice

Which number is in the tens place?

7,180

• 7

• 1

• 8

• 0

Multiple Choice

Which number is in the one's place?

4,230

• 4

• 2

• 3

• 0

Multiple Choice

Which number is in the hundred's place?

9,413

• 9

• 4

• 1

• 3

Regrouping

How do we know when to regroup in subtraction? First, we always start by looking at the ones place. A rhyme I use to remember is, “If there’s more on the floor, you must go next door!”. Here are some examples of when we need to regroup.

Now it's your turn!

Are there “more on the floor”? Do we need to regroup?

Multiple Choice

Do we need to regroup?

• yes

• no

Multiple Choice

Do we need to regroup?

• yes

• no

Multiple Choice

Do we need to regroup?

• yes

• no

How do we regroup in subtraction?

When we “look next door”, we mean go to the next largest place. When regrouping ones, we go to the tens place. Let’s look at an example using base 10 blocks.

Now let’s try one together!

Multiple Choice

When subtracting, which place should we subtract first?

• ones

• tens

• hundreds

Multiple Choice

Do we need to regroup?

• yes

• no

Multiple Choice

Which shows regrouping correctly?

Multiple Choice

What is the final answer?

• 47

• 35

• 37

• 43

Now practice a few on your own!

When I call you back together, we will do a kahoot about subtraction!