21. 250+250*2 (250+250)*2 (480+120): 3 60+90:10*3 60+90:(10*3) 120-80:4*5 84-24+48:6 84-(24+48): 6 100 - 64 +36:4

Решим примеры:

1. 250 + 250 * 2 = 250 + 500 = 750


2. (250 + 250) * 2 = 500 * 2 = 1000


3. (480 + 120) : 3 = 600 : 3 = 200


4. 60 + 90 : 10 * 3 = 60 + 9 * 3 = 60 + 27 = 87


5. 60 + 90 : (10 * 3) = 60 + 90 : 30 = 60 + 3 = 63


6. 120 - 80 : 4 * 5 = 120 - 20 * 5 = 120 - 100 = 20


7. 84 - 24 + 48 : 6 = 84 - 24 + 8 = 60 + 8 = 68


8. 84 - (24 + 48) : 6 = 84 - 72 : 6 = 84 - 12 = 72


9. 100 - 64 + 36 : 4 = 100 - 64 + 9 = 36 + 9 = 45