Answer:
Step-by-step explanation:
a) 7740 ∶ 12 − 10 ∙ 35 + (545 − 280) ∶ 5 =
(7740:12) - (10*35) + (545-280)
= 645 - 350 + 265
= 560
b) (521 + 322 − 412) ∙ 2 − 6864 ∶ 11 + 2 =
{(521 + 322 − 412) ∙ 2} - (6864:11) + 2
= {431 ∙ 2} - 624 + 2
= 862 - 624 + 2
= 240