Pupils need to be able to identify or place four-digit numbers on marked number lines with a variety of scales. Pupils should also be able to estimate the value or position of four-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 Example assessment questions 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 1000 or 100 a given four-digit number is between. To begin with, pupils can use a number line for support. In this example, for the number 8,681, pupils must identify the previous and next multiples of 1,000 and 100.
“The previous multiple of 1,000 is 8,000. The next multiple of 1,000 is 9,000.”
“The previous multiple of 100 is 8,600. The next multiple of 100 is 8,700.”
Pupils need to be able to identify previous and next multiples of 1000 or 100 without the support of a number line. Pupils should then learn to round a given four-digit number to the nearest multiple of 1,000 by identifying the nearest of the pair of multiples of 1,000 that the number is between. Similarly, pupils should learn to round to the nearest multiple of 100. They should understand that they need to examine the digit in the place to the right of the multiple they are rounding to, for example when rounding to the nearest multiple of 1,000 pupils must examine the digit in the hundreds place. Again, pupils can initially use number lines for support, but should be able to round without that support by the end of year 4.
“The closest multiple of 1,000 is 9,000.”
“8,681 rounded to the nearest thousand is 9,000.”
Finally, pupils should also be able to count forwards and backwards from any four-digit number in steps of 1, 10 or 100. Pay particular attention to counting over ‘boundaries’, for example:
- 2,100, 2,000, 1,900
- 2,385, 2,395, 2,405