Carry out column addition and subtraction of numbers involving decimals ( NNS Framework for teaching mathematics, Supplement of examples, Section 6, pages 49, 51)

Associated knowledge and skills

Errors and misconceptions

Tracking charts

Teaching sequences and spotlights

Apply knowledge of the number system to enable efficient counting of a large number of objects.

Add and subtract multiples of ten, a hundred and a thousand.

Has inefficient counting strategies and/or insecure understanding of the number system.

1 Y6
1 Y6
1 Y6

Give an estimate by rounding, to determine whether the answer to a calculation is sensible.

Rounding inaccurately, particularly when decimals are involved, and having little sense of the size of the numbers involved.

2 Y6
2 Y6
2 Y6

Partition whole numbers and decimal numbers, and add and subtract the constituent parts and recombine to complete the calculations.

Has difficulty in partitioning numbers with zero place holders and/or numbers less than one, for example partitioning 0.45 as 0.4 and 0.05.

3 Y6
3 Y6
3 Y6

Add and subtract a pair of numbers that involves crossing boundaries, recognising when to adjust, to compensate and to carry numbers across the boundaries.

Has difficulty in choosing suitable methods for calculations that cross boundaries: addition
Has difficulty in choosing suitable methods for calculations that cross boundaries: subtraction.

4a Y6
4a Y6
4a Y6

4b Y6
4b Y6
4b Y6