a) 284 × 6^9 - 784 × 2^2
= 284 × 10077696 - 784 × 4
= 2862065664 - 3136
= 2862062528
b) ( 999 + 1 ) - ( 4 × 95 )
= 1000 - 380
= 620
c) 72^2 - 89 + 2^7 × 848
= 5184 - 89 + 128 × 848
= 5095 + 108544
= 113639
d) 322 - 233 + 232 × 3232
= 99 + 749824
= 749923