Давай выполним все вычисления по порядку:
1. $$187 + 75 = 262$$
2. $$850 - 86 = 764$$
3. $$238 + 93 = 331$$
4. $$540 + 30 = 570$$
5. $$540 + 300 = 840$$
6. $$540 + 330 = 870$$
7. $$17 * 4 : 2 = 68 : 2 = 34$$
8. $$28 * 3 : 4 = 84 : 4 = 21$$
9. $$18 * 5 : 3 = 90 : 3 = 30$$
10. $$42 : 14 * 26 = 3 * 26 = 78$$
11. $$60 : 12 * 14 = 5 * 14 = 70$$
12. $$90 : 15 * 13 = 6 * 13 = 78$$
Ответы:
1. 262
2. 764
3. 331
4. 570
5. 840
6. 870
7. 34
8. 21
9. 30
10. 78
11. 70
12. 78