Week 6 - 8 Decimals

National curriculum content

Recognise and use thousandths and relate them to tenths, hundredths and decimal equivalents
Solve problems involving number up to three decimal places
Multiply and divide whole numbers and those involving decimals by 10, 100 and 1000

Lesson objectives

What we want children to know

To apply their knowledge of place value to decimals
That the decimal point does not move
To understand that ten tenths equals 1 whole, 100 hundredths equals one whole and how these relate to each other in the context of calculation
How to use place holders in context to support calculation
Pupils should go beyond the measurement and money models of decimals, for example, by solving puzzles involving decimals

What skills we want children to develop

Use knowledge to solve reasoning and problem solving questions such as:

Here are four calculations.

Which one is the easiest to answer?

Which one is the trickiest to answer?

Explain your choice of order.

0.45 − 0.3 =

0.45 − 0.15 =

0.45 − 0.23 =

0.45 − 0.18 =

Use this number sentence to write down three more pairs of decimal numbers

that sum to 3:

1·6 + 1·4 = 3

Dexter and Annie have some money.

Dexter has £3.45 more than Annie.

They have £12.45 altogether.

How much money does Annie have? Use a bar model to help.

Mathematical Talk

What is the number represented on the place value chart? What digit changes when I add a hundredth?
If I’m taking away tenths, which digit will be affected? Is this always the case? How many hundredths can I take away before the tenths place is affected?
How would partitioning a number help us? How do you decide what number to partition? Why is partitioning 0.67 into 0.55 and 0.12 more helpful than 0.6 and 0.07?
Why is the position of the decimal point important?
What happens when you need to subtract a greater digit from a smaller digit e.g. 3 hundredths subtract 4 hundredths?

Cotmanhay Junior School