One adjustment to Y3 – ‘hundreds’ ‘tens’ 437 182 = 255 – Two adjustments to to – ‘hundreds’ ‘tens’, ‘tens’ ‘ones’ 432 187 = 245 – Introduce money for decimals Y4 £3.25 - £2.39 = £0.86 or 86p Extend method to numbers with at least 4 digits Use the compact method to subtract two or more decimal fractions with at least four Y5 digits and 2 or 3 decimal places for money/measures, eg, time to thousandths of a second. Mo Farrah ran the first two laps of his 10km race in 96.437 seconds. The second lap took 49.295 seconds. How long did it take him to run the first lap? Know that the decimal points should line up under each other, particularly when adding or subtracting mixed amounts, eg, 43.2m 2900cm – Y6
One adjustment – ‘hundreds’ to ‘tens’ 437 – 182 = 255 Two adjustments – ‘hundreds’ to ‘tens’, ‘tens’ to ‘ones’ 432 – 187 = 245 Introduce money for decimals £3.25 - £2.39 = £0.86 or 86p Extend method to numbers with at least 4 digits Use the compact method to subtract two or more decimal fractions with at least four digits and 2 or 3 decimal places for money/measures, eg, time to thousandths of a second. Mo Farrah ran the first two laps of his 10km race in 96.437 seconds. The second lap took 49.295 seconds. How long did it take him to run the first lap? Know that the decimal points should line up under each other, particularly when adding or subtracting mixed amounts, eg, 43.2m – 2900cm Y3 Y4 Y5 Y6
Calculation-Policy-Written-Subtraction.docx