1) 420=6*7*10
2) а) 40*2=80
б) 40/2=20
в) 120/40 = 3
г) 80/2 = 40
3) 1) 80*5 = 400
2) 420 / 60 = 7
3) 7 * 8 = 56
4) 400+ 56 = 456
1) 480-180 = 300
2) 300 / 6 = 50
3) 690 - 50 = 640
4) 692 / 4 = 173
50 * 4 + 173 * 4 = 200 + 692 = 892
173 * 3 + 173 = 173 * (3+1) = 173 * 4 = 692
692 - 173 * 3 = 173 * 4 - 173*3 = 173 * (4-3) = 173 * 1 = 173
5) 6982*4+162 = 27928 + 162 = 28090
8197*30+29 = 245910 + 29 = 245939
6) 12/4=3(см)
(3+6)*2=18 (см квадратных)