Так...
5*10-2*10+7*100+9*100-100=
1. 5 * 10=50
2. 2*10 = 20
3. 7*100 = 700
4. 9*100 = 900
5. 50 - 20 = 30
6. 30 + 700 = 730
7. 730 + 900 = 1.630
8. 1630 - 100 = 1530
ответ: 1530
Так...
5*10-2*10+7*100+9*100-100=
1. 5 * 10=50
2. 2*10 = 20
3. 7*100 = 700
4. 9*100 = 900
5. 50 - 20 = 30
6. 30 + 700 = 730
7. 730 + 900 = 1.630
8. 1630 - 100 = 1530
ответ: 1530