KS2 lesson: Decimal Numbers

Learning Objectives:

  • Using a number line
  • Partitioning decimals
  • Compare decimals
  • Rounding decimals

Key words: Number line, decider, decimal point, less then, greater then,

It is easy to understand decimals using a number line

Number Sequences with decimals

Number sequences are about counting on or counting back

Start counting the decimals between 4 and 5 adding 0.2

Now let’s count from 4 to 6 using the same method adding 0.4 :

4.0;  4.4;  4.8;  5.2;  5.6;  6

Other examples:

0; 0.5; 1.0; 1.5; 2.0; 2.5; 3.0;

0; 0.3; 0.6; 0.9; 1.2; 1.5; 1.8;

0; 0.4; 0.8; 1.2; 1.6; 2.0; 2.4;

 Partitioning decimals

Any decimal number has a whole number part and a decimal part

3.24=          3      +        0.24
whole        decimal

There are other ways of partitioning a decimal number:

4.25 = 1+3+ 0.20+ 0.05

71.2 = 70+ 1+ 0.2

1.47 = 1+ 0.47

Decimals can be compared

To compare numbers you need to use Inequality symbols:   

>  means “is less then ”

2.1 because the whole number is bigger

2.3 2.4        or       4.2=>2.4

5.3>4.2         or       5.3=>4.2

7.4 round up

4 d.p-  4.0164-  the decider is 2 round down

3 d.p-  4.016- the decider is 4 round down

Need to practice? Download  here a free decimal worksheet

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