(i)
23 x 72 + 77 x 72
= 72(23 + 77)
= 72 x 100 = 7200
(ii)
56 x 25 – 25 × 39 – 25 x 17
25(56 – 39 – 17)
= 25 x (56 – 56)
= 25 x 0 = 0
(iii)
27 x 47 + 55 x 8 + 27 x 53 + 45 x 8
= 27 x 47 + 27 x 53 + 55 x 8 + 45 × 8
= 27 x (47 + 53) + 8(55 + 45)
= 27 x 100 + 8 x 100
= 2700 + 800 = 3500