tính nhanh :
a, 53 + 8 + 53 + 53 c, ( 8 + 8 x 7 - 9 ) x ( 9 x 9 - 81 )
b, 24 x 2 x 2 + 2 x 12 x 6 d, ( 15 x 3 - 11 x 2 - 10 ) x ( 405 : 5 - 81 )
Tính nhanh :
a, 53 + 8 + 53 + 53 c, ( 8 + 8 x 7 - 9 ) x ( 9 x 9 - 81 )
b, 24 x 2 x 2 + 2 x 12 x 6 d, ( 15 x 3 - 11 x 2 - 10 ) x ( 405 : 5 - 81 )
Tính nhanh :
a, 53 + 8 + 53 + 53 c, ( 8 + 8 x 7 - 9 ) x ( 9 x 9 - 81 )
b , 24 x 2 x 2 + 2 x 12 x 6 d, ( 15 x 3 - 11 x 2 - 10 ) x ( 405 : 5 - 81 )
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)
Tìm x biết:
a, (x + 9)×9 = 81
b, (x + 24)÷9 = 7
c, x - 56 = 8×9
d, x + 25 = 9×10
Tìm x:
a, x nhân 3/8 = 9/16
b, x :12/7 = 5/8
(2 điểm) Tính
a) 5 x 7 + 14
b) 48 : 6 + 13
c) 6 x 8 – 26
d) 24 - 4 x 5
x = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 .
x = 2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + 20 .
x = 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 .
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