2 x 2 + 5 =?
3 x 3 +1 =?
3 x 2 + 1 =?
Tính nhẩm:
a) 2 x 2 = ...... 3 x 3 = ......
2 x 4 = ...... 3 x 5 = ......
2 x 6 = ...... 3 x 7 = ......
2 x 8 = ...... 3 x 9 = ......
4 x 4 = ...... 5 x 5 = ......
4 x 2 = ...... 5 x 7 = ......
4 x 6 = ...... 5 x 9 = ......
4 x 8 = ...... 5 x 3 = ......
b) 200 x 4 = ...... 300 x 2 = ......
200 x 2 = ...... 300 x 3 = ......
400 x 2 = ...... 500 x 1 = ......
100 x 4 = ...... 100 x 3 = ......
tìm x
a) 39/7 : X =13
b) 2/3 . X + 1/2 = 1/10
c) X : 8/11 = 11/3
d) 2/9 - 7/8 . X = 1/3
1 x 1 + 3 x 3 + 5 x 5 + 7 x 7 + 9 x 9 = ?
2 x 2 + 4 x 4 + 6 x 6 + 8 x 8 = ?
b) 200 x 4 = ...... 300 x 2 = ......
200 x 2 = ...... 300 x 3 = ......
400 x 2 = ...... 500 x 1 = ......
100 x 4 = ...... 100 x 3 = ......
Tính nhẩm:
Cách làm: 200 x 3 = ?
Nhẩm: 2 trăm x 3 = 6 trăm
Vậy: 200 x 3 = 600
200 x 2 = 300 x 2 =
200 x 4 = 400 x 2 =
100 x 5 = 500 x 1 =
20 x 1 + 20 x 2 + 20 x 3 + 20 x 4 + 20 x 5 + 20 x 6 = ?
1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x ... x 100 = ?
Tính nhẩm
a) 6 x 2 = ..... 6 x 3 = ..... 6 x 8 = ..... 6 x 1 = .....
6 x 4 = ..... 6 x 5 = ..... 6 x 9 = ..... 1 x 6 = .....
6 x 6 = ..... 6 x 7 = ..... 6 x 10 = ..... 0 x 6 = .....
b) 6 x 5 = ..... 6 x 4 = ..... 3 x 6 = ..... 2 x 6 = .....
5 x 6 = ..... 4 x 6 = ..... 6 x 3 = ..... 6 x 2 = .....
a .(18 – 9 x 2) x (2 + 4 + 6 + 8 + 10)
b.(7 x 8 – 56 ) : (2 + 4 + 6 + 8 + 112)
c. (2 + 125 + 6 + 145 + 112) x (42 – 6 x 7)
d.(12 x 6 – 12 x 4 – 12 x 2) x ( 347 + 125)
e(a x 7 + a x 8 – a x 15) : (1 + 2 + 3 + ........ + 10)
f.58 – 58 x (6 + 54 – 60)
g.32 + 63 x a x ( a x 1 – a : 1) + 32 x 8 + 32
h.(1 + 2 + 3 + 4 + .... + 9) x (21 x 5 – 21 – 4 x21)
i.(9 x 7 + 8 x 9 – 15 x 9) : (1 + 3 + 5 + 7 + ........+ 17 + 19)
k.(2 + 4 + 6 + 8 + ... + 20) x (56 x 3 – 72 : 9 x 21)