а) 360 : 6 × 5 - 450 : (25 × 2) - 70 × 6 : 3
1) $$360 : 6 = 60$$
2) $$60 \times 5 = 300$$
3) $$25 \times 2 = 50$$
4) $$450 : 50 = 9$$
5) $$70 \times 6 = 420$$
6) $$420 : 3 = 140$$
7) $$300 - 9 - 140 = 151$$
Ответ: 151
б) 4 × (30 × 8) - 9 × 8 : 12 - (100 – 8 × 8)
1) $$30 \times 8 = 240$$
2) $$4 \times 240 = 960$$
3) $$9 \times 8 = 72$$
4) $$72 : 12 = 6$$
5) $$8 \times 8 = 64$$
6) $$100 - 64 = 36$$
7) $$960 - 6 - 36 = 918$$
Ответ: 918