Calculate amounts up to 20 p | Maths | Quizalize & Oak National Academy

Starter quiz

Which coins show the most efficient way to make 13 p?
Which coins show the most efficient way to make 11 p without using a 10 p coin?
Here is a set of coins. Which totals can be made using only two of these coins? Can you find three different totals?

11 p ✓

12 p ✓

3 p ✓

13 p
Which item can Alex buy using only two coins?

the pear ✓

the melon

the banana
Which statements are correct?

I can make 11 p with one 10 p and one 1 p coin. ✓

I can make 11 p with two 5 p coins and one 1 p coin. ✓

I can make 11 p using only 2 p coins.
Alex has four coins of the same value. Their total value is 20 p. Which of the following does he have?

Four 2 p coins

Four 5 p coins ✓

Four 10 p coins

Exit quiz

Which ten frame represents 13 p?
Who has the most money - Jun or Sofia?

Sofia ✓

Jun
Sofia represents 12 p on a part-part-whole model. What is the missing part?

2 p

10 p ✓

1 p
What could we say is the most efficient way to add 2 p, 5 p, 10 p and 2 p?

2 p + 5 p + 2 p + 10 p

10 p + 2 p + 5 p + 2 p

10 p + 5 p + 2 p + 2 p ✓
Jun wants to count the coins as efficiently as possible. What could you tell him to help him?

Put coins with the same value together. ✓

Put coins that are the same size together.

Start with the coin with the greatest value. ✓

Start with the coin with the smallest value.
Match the amounts that are equal.

10 p + 2 p + 2 p

⇔

5 p + 5 p + 2 p + 2 p ✓

5 p + 5 p + 5 p

⇔

5 p + 10 p ✓

10 p + 5 p + 2 p

⇔

5 p + 2 p + 10 p ✓

Worksheet

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Lesson Details

Key learning points

Coins can be added in any order, but it is more efficient to group coins of the same value together.
It is more efficient to add the greatest value coins first, or find coins that will help with using a mental strategy.
When adding coins, known strategies can be used to help add efficiently.
A number line can be used to help keep track of the coins added.

Common misconception

Children may start counting with the first coin they see or arranged them in a line in no particular order, leading to inefficient counting strategies instead of more efficient calculation methods.

Encourage children to group coins of the same value together and start with higher value coins, so they can apply the calculation strategies they already know to find the total value of a set of different coins.

Keywords

Efficiently - Not wasting time or effort. An efficient strategy is one we can carry out easily.