y x 2 x 2 = 40
y x 4= 40
y=40:4
y=10
Vậy y=10
y x 2 x 2 = 40
y x 4 =40
y = 40:4
Vậy y = 10
Tìm y
40/5 : (y x 2/5) = 20/5
Tính nhẩm
8 x 2 = ...... 8 x 4 = ...... 8 x 7 = ...... 8 x 5 = ......
16 : 8 = ..... 32 : 8 = ..... 56 : 8 = ..... 40 : 8 = .....
16 : 2 = ..... 32 : 4 = ..... 56 : 7 = ..... 40 : 5 = .....
60 x 2 = ?
50 x 2 = ?
40 x 2 = ?
90 x 2 = ?
100 x 2 = ?
Tính nhẩm:
| 20 x 4 = ....... | 200 x 3 = ....... | 2000 x 2 = ....... |
| 30 x 4 = ....... | 300 x 3 = ....... | 3000 x 2 = ....... |
| 40 x 4 = ....... | 400 x 3 = ....... | 4000 x 2 = ....... |
a) x + 40*25 = 2000;
b) (x + 40)*25 = 2000;
c) (x - 10)*5 = 100 - 20*4;
d) (x + 2) + (x + 4) + ... + (x + 1996) = 998000.
40 + 30 + 50 + 70 + 8 + 65 + 12 + 30 +40 + 5 x 2 + 21 x 23 = ?
x + 70 = 40 x 2
x + 40 = 30 x 2
x + 50 = 40 x 2
