Minds On

How many bowling pins?

Polkaroo and his friend are bowling.

Examine the following images. What do you notice?

Brainstorm

Brainstorm

Answer the following questions. Share your thoughts with a partner, if possible.

  • How many pins did they start with?
  • How many pins did they knock down?
  • How many pins are left?

Hint: try counting the number of pins in each image to answer each question

Action

Bowling fun

Let’s bowl with Polkaroo and his friend and learn how to subtract numbers.

Check out this video entitled “Polkaroo Counts: Subtraction” to learn more about how to subtract.

As Polkaroo and Angela bowl, they knock down pins. When pins are knocked down, they get removed.

Let’s explore how many pins there are left throughout Polkaroo and Angela’s game!

Let’s play!

Polkaroo and Angela set up 10 pins.

Angela goes first and knocks down 4 pins.

How many pins are left?

Let’s explore a number line to show how many pins are left.

A number line from 0 to 10 with a dot at the number 10 and curved arrows moving back one unit at a time until it reaches the number six.

We start at 10 and jump backwards, or count back, 4 numbers.

We land at 6.

So, 10 − 4 = 6

This tells us that the number of pins leftover is 6.

Polkaroo’s turn!

Now, they start with 6 pins.

Polkaroo goes next and knocks over 3 pins.

How many pins are left?

6 − 3 = ?

Use a number line, drawings, or counters to solve the problem and show your thinking.

A small red ball knocking down 3 out of the 6 bowling pins on a flat grassy area.

Press ‘Sample answer’ to access how many pins are left.

6 − 3 = 3

A number line from 0 to 10 with a dot at number 6 and curved arrows moving back one number at a time until it reaches 3.

Let’s play again!

Three bowling pins on a flat grassy surface.

Polkaroo and Angela want to start over.

They need to reset the game. There are 3 pins still standing from the last round. A new game starts with 10 pins.

Try It

Try it

How many pins do they need to add to reset the game to 10?

Use a number line, drawings, counters, or another method of your choice to show your thinking.

Press ‘Sample answer’ to find out how many pins Polkaroo and Angela need to add to reset the game.

Polkaroo and Angela need to add 7 pins to get a total of 10 pins.

Two groups of pins. One group has 3 pins and one group has 7 pins. Underneath is the addition sentence 3 plus 7 equals 10.

For each sentence, select the missing word from the drop-down menu.

Consolidation

Ball toss

9 cans stacked on a table. 4 are on the bottom, 3 in the middle, and 2 on top.

Polkaroo decides to play the game Ball Toss.

He sets up 9 cans.

He tosses a ball and knocks down 4 cans.

Nine cans in formation with 4 on the bottom, 3 in the middle and 2 on the top. A small red ball is knocking down the top 2 cans and 2 cans from the middle.

How many cans does he have left?

Use a number line, drawings, counters, or another method of your choice to show your thinking.

Fill in the blanks to create a number sentence that shows what happened in the game, from start to finish.

A subtraction sentence. There is a black line and an arrow underneath with a label that says number of cans at the start. Then there is a minus sign next to it. Then there is a black line and an arrow underneath with a label that says number of cans knocked down. Then there is an equal sign next to it. Then there is a black line with an arrow underneath and a label that says number of cans left over.

Try It

Try it

Polkaroo wants to play the game with his friends and needs to reset the cans.

There are 2 cans already set up. A new game starts with 9 cans.

How many cans does Polkaroo need to add to reset the game to 9?

Use a number line, drawings, counters, or another method of your choice to show your thinking.

Reflection

How do you feel about what you have learned in this activity?  Which of the next four sentences best matches how you are feeling about your learning? Press the button that is beside this sentence.

I feel...

Now, record your ideas about your feelings using a voice recorder, speech-to-text, or writing tool.