Question

Can you do these in your head?

(i) (135 − 73) − 27

(ii)

(iii) (298 − 4.5) − 3.5

Answer 1

(i) (135 − 73) − 27

= 135 − (73 + 27) {Using (x − y) − z = x − (y + z)}

= 135 − 100

= 35

(ii)

(iii) (298 − 4.5) − 3.5

= 298 − (4.5 + 3.5) {Using (x − y) − z = x − (y + z)}

= 298 − 8

= 290