Self-assessment questions
 

Self-assessment questions

Identify the errors made by the pupils in the examples in Figure 1/ page ?

Find the answer to 538 + 294 by the front-end approach, that is, by partitioning the numbers into hundreds, tens and ones, then starting with the hundreds and working from left to right.

Calculate 423 + 98 mentally, using compensation.

Calculate 297 + 304 mentally, by relating it to a double.

Calculate 494 + 307 mentally, using 500 as a stepping stone.

Calculate 26 + 77 mentally, by relating the numbers to multiples of 5.

Calculate 1000 – 458 mentally, using compensation.

Calculate 819 – 523 mentally, by making one of the numbers more friendly.

Calculate 732 – 389 mentally, by adding-on from 389, using 400 and 700 as

stepping stones.

Do these using any mental strategies that seem appropriate: (a) 974 – 539; (b) 400 -

237; (c) 597 + 209; (d) 7000 – 6; (e) 7000 – 6998.