(a) 297 × 17 + 297 × 3

As we can clearly see it is in the form of;

= ab+ac

= a(b+c)

So,

= 297 × (17+3)

= 297 + 20

= 5940

(b) 54279 × 92 + 8 × 54279

= 54279 × (92+8)

= 54279 × 100

= 5427900

(c) 81265 × 169 – 81265 × 69

= 81265 × (169-69)

= 81265×100

= 8126500

(d) 3845 × 5 × 782 + 769 × 25 × 218

= 3845×5×782+769×5×5×218

= 3845×5×782+3845×5×218

= 3845×5 × (782+218)

= 19225×1000

= 19225000