Three-digit Numbers in the Linear Number System (1)
Pupils need to be able to identify or place three-digit numbers on marked number lines with a variety of scales.
Pupils should also be able to estimate the value or position of three-digit numbers on unmarked numbers lines, using appropriate proportional reasoning. Pupils should apply this skill to taking approximate readings of scales in measures and statistics contexts, as shown in the 3NPV–3 below.
For more detail on identifying, placing and estimating positions of numbers on number lines, see year 2, 2NPV–2. Pupils must also be able to identify which pair of multiples of 100 or 10 a given three-digit number is between.
To begin with, pupils can use a number line for support. In this example, for the number 681, pupils must identify the previous and next multiples of 100 and 10.
“The previous multiple of 100 is 600.
The next multiple of 100 is 700.”
“The previous multiple of 10 is 680. The next multiple of 10 is 690.”