A decimal number has a decimal point followed by digits that show the fractional part.

The process of unitising and exchanging between place values is known as regrouping. For example: ten ones can be regrouped for one ten.

The value of a digit in a number based on where it is placed.

Use knowledge of column addition and subtraction to calculate with decimal numbers

Maths

Explain that decimal numbers with tenths can be composed additively

Explain that decimal numbers with tenths can be composed multiplicatively

Use known facts and mental strategies to calculate with decimal numbers within and across a whole

Use representations to round a decimal number with tenths to the nearest whole number

In this unit pupils will calculate with decimal numbers using column addition and subtraction. In the future unit pupils will identify hundredths as part of a whole and describe and represent hundredths as a decimal fraction. They will compare and order decimal numbers with hundredths.

In the prior unit pupils identified tenths as part of a whole and describe and represented tenths as a decimal fraction. They counted tenths in different ways and compared and ordered decimal numbers with tenths. In this unit pupils will calculate with decimal numbers using column addition and subtraction.

In this unit pupils will extend their understanding of formal calculation strategies to use column methods to add and subtract with decimal numbers.

Compose and calculate with decimals including column addition and subtraction

The decimal points are not lined up correctly.

Although adding decimals, there is no decimal point within the sum.

Tick the explanation that explains why the column addition is laid out incorrectly.

Complete the column addition and tick the correct answer.

Complete the column subtraction and write in the correct answer.

How many regroupings does this calculation require?

Look at the column subtraction. What is the missing digit?

Tick the calculations where the missing number is greater than 5.

Tick all the expressions that would make or bridge 10.

Order the expressions from the smallest amount to the largest amount.

Complete the column addition and write in the answer.

Complete the column subtraction and write in the answer.

Tick the calculations that require a regrouping.

They have forgotten to reduce the tens to 6 tens when they regrouped.

Tick the correct explanation of the mistake that has been made.

Use knowledge of column addition and subtraction to calculate with decimal numbers

Lesson outcome