Multiplying by 11

Multiplying by 11

What will we be doing today?

Today we will practice using the splitting strategy to multiply by 11.

Multiple Choice

Do you remember the egg carton? How many eggs will fill this carton?

• 12

• 11

• 13

• 10

Let's Imagine

Today we will imagine that we have a chicken farmer who keeps one egg from each carton to feed his family.

• So even though 12 eggs will fill a carton, there will now only be 11 eggs since the farmer needs to feed his family.

Stack of six

There are six cartons.

• There are 11 eggs in each carton.

• So, we have six groups of 11.

• How many eggs are there?

11​
​11
11​
11​
11​
11​

Draw

What addition equation shows that there are 66 eggs in all?

Draw

What multiplication equation shows that there are 66 eggs?

Let's use splitting

Now I'll show another way.

• I will split each carton so that there are 10 eggs in one part and 1 egg in the other part.

​Using Splitting on our Egg Carton	​
​10	​1
10​	1​
10​	1​
10​	1​
10​	1​
10​	1​

Draw

There are six groups of 10 eggs each on the left side. How much is 6 times 10?

Draw

There are six groups of 1 egg each on the right side. How much is 6 times 1?

Draw

How much is 60 plus 6?

Draw

How many eggs are there in all?

​Let's Stack three cartons!

​Stacking 3 cartons
​11
​11
​11

Draw

What multiplication problem do we need to solve to figure out how many eggs are in the cartons?

Draw

How would our cartons look if we used splitting?

​Splitting with a carton of 3 eggs

If you don't remember that 3 times 11 equals 33.

• You can figure it out by splitting.

• I will split the carton into 10 and 1 because it's easy to multiply by 10.

​Splitting a Carton of 3 Eggs	​
​10	​1
​10	​1
​10	​1

Draw

Use the splitting strategy to figure out how many eggs are in nine egg cartons if each carton has 11 eggs.

We will work on worspace pages 9 and 10.

​

​Time to Wrap it up!!!