А-(490:7), а=100, 200, 300
100-(490:7)=100-70=30
200-(490:7)=200-70=130
300-(490:7)=300-70=230
А) (6 - 2,43) : 4 1/4 = 0,84
1) 6 - 2,43 = 3,57
2) 3,57 : 4 1/4 = 3,57 : 4,25 = 0,84
Пояснения: 1/4 = 25/100 = 0,25
б) 15,96 : (9/25 + 2,04) = 6/65
1) 9/25 + 2,04 = 0,36 + 2,04 = 2,4
2) 15,96 : 2,4 = 6,65
Пояснения: 9/25 = 36/100 = 0,36
7/23 + 16/23 = 23/23 = 1
5/13 + 15/26 =10/26 + 15/26 = 25/26
3/10 +49/100 =30/100 + 49/100 = 79/ 100
2/7 × 3/5 = 6/ 35
8/ 15 ÷ 16/ 45 = 8/ 15 × 45/ 16 = 3/2
96000:300= 320
96000 / 300
-900 ----------
------- 320
600
- 600
----------
0