New
New
Year 5

Explain that decimal numbers with tenths can be composed additively

I can explain that decimal numbers with tenths can be represented as addition.

New
New
Year 5

Explain that decimal numbers with tenths can be composed additively

I can explain that decimal numbers with tenths can be represented as addition.

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Lesson details

Key learning points

1. Use part-part-whole models to partition decimal numbers into the whole number and fraction parts.
2. Number with whole number and decimal parts can be represented as addition and subtraction equations.
3. The whole number and decimal parts of a number can be represented on a number line.

Common misconception

Pupils understand the equals sign as 'where the answer is' rather than equality between expressions.

Spend time moving addition and subtraction expressions to either side of the equals sign using numbers within 10 before moving to tenths.

Keywords

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

• Partition / partitioning - Partitioning is the act of splitting an object or value down into smaller parts..

• Equation - An equation is used to show that one number, calculation or expression is equal to another. For example: 3 + 4 = 7

• Expression - An expression contains one or more values, where each value is separated by an operator. For example: 3 + 4

Make the connections between tenths written in decimal form and fractional form and encourage pupils to write a range of equations using both of these representations.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Starter quiz

6 Questions

Q1.
Tick the representations that are expressions.
5 + 0.4 = 5.4
5 = 5.4 - 0.4
Q2.
In this part-part-whole model, which value represents the whole?
2
5
Q3.
If 56 was to be partitioned into tens and ones, what would each part be?
5 and 6
60 and 5
5 and 0.6
Q4.
Which equations represent this part-part-whole model?
Correct answer: 40 + 9 = 49
9 + 49 = 40
Correct answer: 9 + 40 = 49
40 + 49 = 9
Q5.
Complete the sentence. is one tenth the size of 4.
Q6.
Write the following mixed number as a decimal.
Correct Answer: 3.8, three point eight

Exit quiz

6 Questions

Q1.
Fill in the missing number: 3 + 0.4 = ___
0.34
34
Q2.
Which part-part-whole model would not represent 0.6 + 3 = 3.6
Correct Answer: An image in a quiz
Q3.
What is the missing part: 5.6 = 5 + ___
6
6.0
1
Q4.
Which equation would not represent the part-part-whole model.
7.2 = 7 + 0.2
7.2 − 7 = 0.2
Correct answer: 0.2 = 7 − 7.2
0.2 + 7 = 7.2
Q5.
Look at the image. Match the missing number to the equation where it is required.
Correct Answer:A,4.6 − ___ = 0.6

4.6 − ___ = 0.6

Correct Answer:B,4 = 4.6 − ___

4 = 4.6 − ___

Correct Answer:C,0.6 = ___ − 4

0.6 = ___ − 4

Q6.
Alex is 1 m tall. Andeep is 1.3 m tall. How much taller is Andeep than Alex? Remember to include the correct unit of measure in your answer
Correct Answer: 0.3 m, 0.3m, 3 tenths, 0.3 , 0.3 metres