a: =31(175-50)+69*125
=125*69+125*31
=12500
b: \(=205-\dfrac{1200-\left(16-6\right)^3}{40}=205-\dfrac{1200-1000}{40}=205-5=200\)
2023 x 14 + 2023 x 83 +97
78 x 31 + 78 x 24 + 78 x 17 + 78 x 22 x 72
371 x 69 + 371 x 14 + 629 x 83
91 x 51 + 49 x 163 - 49 x 72
3 x 12 x 17 + 4 x 9 x 81 + 2 x 6 x 6
42 x 17 + 58 x 83 x 42 x 83 + 42 x 83 + 58 x 17
tính bằng cách hợp lý nhất
a,2 x 31 x 12 +4 x 6 x 42 +8 x 27x 3
b, 36x 28 + 36 x 82 + 64 x 69+ 64 x 41
Tính nhanh
G= 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3
C = 46 - 45 + 44 -43 + 42 - 41 + .... + 2 -1
I = 7 x 48 x 6 + 21 x 12 x 2 +14 x 40 x 3
( Giải ra )
B , ( 2/15 + 3/40 + 4/96 + 5/204 + 6/391 ) *x ( x-1) =20/69
A , ( 1/4 + 1/28 + 1/70 + ...... + 1/8554 ) *x = 31/94
26,72 + 13/100 + 21/40
1/4 + 17/50 + 31/100
3/4 + 15/40 + 69/300
42/700 + 42/120 + 17/80
tính nhanh
25/37 x 18/29 + 18/29 x 12/37
31/85 x 11/19 + 31/85 x 12/19 - 42/19 x 31/85
c , 16/53 : 17/9 - 16/53 : 17/8
1/5 x 12/31 x 4/3 + 19/31 x 4/15
1) 31-3 ( x+2 ) = 7
2) 175-25 ( 2x - 1 ) = 175
3) 25 - x/2 = 19
4) 2 ( x-1 ) + 3 = 15
1.tính hợp lí
31/53 x 17/28 + 31/28 x 11/53
C= 46 - 45 + 44 - 43 + 42 - 41 + ... + 2- 1
G = 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3
I = 7 x 48 x 6 + 21 x 12 x 2 + 14 x 40 x 3
K = 1 + 7 + 8 + 15 + 23 + ... + 160
