1)240x15-80x6x3-60x4
=240x15-80x3x6-240x1
=240x15-240x6-240x1
=240x(15-6-1)
=240x8
=1920
2)150x5x3x6-15x11
150x5x6x3-15x10-150x0,2
=150x5x6x3-150x1-150x0,2
=150x(5+6+3-1-0,2)
=150x12,8
=1980
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)
Find the values of these espressions :
25 - (20 - 10)
80 - (30 + 25
125 + (13 + 7)
416 - (25 - 21)
(65 + 15) x 2
46 : (6 : 3)
(74 - 14) : 2
81 : (3 x 3)
123 x (42 - 40)
(100 + 11) x 9
72 : (2 x 4)
64 : (8 : 4)
Tính nhanh:
(18 - 9 x 2 ) x ( 2 + 4 + 6 + 8 + 10)
(18 – 9 x 2) x (2 + 4 + 6 + 8 + 10)
(7 x 8 – 56 ) : (2 + 4 + 6 + 8 + 112 )
(2 + 125 + 6 + 145 + 112) x (42 – 6 x 7)
(12 x 6 – 12 x 4 – 12 x 2) x ( 347 + 125)
(a x 7 + a x 8 – a x 15) : (1 + 2 + 3 + …….. + 10)
58 – 58 x (6 + 54 – 60)
32 + 63 x a x ( a x 1 – a : 1) + 32 x 8 + 32
(1 + 2 + 3 + 4 + …. + 9) x (21 x 5 – 21 – 4 x21)
(9 x 7 + 8 x 9 – 15 x 9) : (1 + 3 + 5 + 7 + ……..+ 17 + 19)
(2 + 4 + 6 + 8 + … + 20) x (56 x 3 – 72 : 9 x 21)
Phiền nêu cách làm luôn nhé, xin cảm ơn
Tính giá trị của biểu thức:
a) 15 + 15 x 5 = ....................
= ....................
b) 60 + 60 : 6 = ....................
= ....................
c) ( 60 + 60) : 6 = ....................
= ....................
Tính nhẩm:
6 x 9 =
28 : 7 =
7 x 7 =
56 : 7 =
7 x 8 =
36 : 6 =
6 x 3 =
48 : 6 =
6 x 5 =
42 : 7 =
x 5 =
40 : 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 .
Tính nhẩm
6 x 4 = ..... 12 : 6 = ..... 7 x 3 = ..... 63 : 7 = .....
7 x 5 = ..... 42 : 7 = ..... 6 x 8 = ..... 48 : 6 = .....
6 x 6 = ..... 28 : 7 = ..... 7 x 8 = ..... 49 : 7 = .....
Bài 3. Tìm x. x/36 = 3/4 ; x/7 = 56/49 ; 15/27 = 5/x ; 3/7 = 42/x
Đặt tính rồi tính:
a) 14 x 6 20 x 5 34 x 7 66 x 6
......... ........... .......... ...........
......... ........... .......... ...........
......... ........... .......... ...........
b) 86 : 2 63 : 3 80 : 4 83 : 4
......... ........... .......... ...........
......... ........... .......... ...........
......... ........... .......... ...........
