B = 107 - {38 + [7 . 32 - 24 : 6 + (9 - 7 )3]} : 15
B = 107 - {38 + [7 . 9 - 24 : 6 + 23]}: 15
B = 107 - {38 + [63 - 4 + 8]} : 15
B = 107 - {38 + [59 + 8]} : 15
B = 107 - {38 + 67} : 15
B = 107 - 105 : 15
B = 107 - 7
B = 100
Vậy B = 100.
bài 1: Tính nhanh
a/ -3/7 + 15 /26 - ( 2/13 - 3/7 )
b/ 2 3/7 + 2/9 - 1 3/7
c/ ( 377 /-231 - 124/89 + 34/791 ) x ( 1/6 - 1/8 - 1/24 )
bài 2: Thực hiện phép tính :
a/ 1/2 x ( 2/9 + 3/ 12 - 5/27 ) b/ ( -5/28 +1,75 + 8/35 ) : -3 9/20
c/ 1/3 x 5/7 - 3/2 x 26/14 d/ 70,5 - 528 : 15/2
1. Tính
a, 1+7+8+15+23+...+160
b, 17+4+5+9+19+...+60+9
c, 78*3+78*24+78*17*22*72
d, 53*39+47*39+47-53*21-47*21
e, 2*53*12+4*6*87-3*8*40
g, 5*7*77-7*60+49*25-15*42
h, 1*2+2*3+3*4+...+2016*2017
tính nhanh :
a) \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
b) \(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
c) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
d) \(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
tính
67-[8+7.3^2-24:6+(9-7)^3]:15
dấu "." là dấu nhân
Bài 1 : Bỏ dấu ngoặc rồi thu gọn biểu thức:
a)A=(a+b)-(a-b)+(a-c)-(a+c)
b)B=(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
Bài 2 :
a) thực hiện phép tính;
(-5/28+1,75+8/35):(-3\(\frac{9}{20}\))
b) tính nhanh
1/ -3/7+15/26-(2/13-3/7) 2/ 2.3/7+(2/9-1\(\frac{3}{7}\))-5/3:1/9
3/ -11/23.6/7+8/7.-11/23-1/23 4/ (377/-231-123/89+34/791).(1/6-1/8-1/24)
Bài 1: Tìm x , biết:
1) x - 2 = -6 12) 3 . | x - 1 | - 5 = 7
2) -5 . x - ( -3 ) = 13 13) -12 . ( x - 5 ) + 7 . ( 3 - x ) = 5
3) 15 - ( x - 7 ) = -21 14) ( x - 2 ) . ( x + 4 ) = 0
4) 3 .x + 17 = 2 15) ( x - 2 ) . ( x + 15 ) = 0
5) 45 - ( x - 9 ) = -35 16) ( 7 - x ) . ( x + 19 ) = 0
6) ( -5 ) + x = 15 17) -5 < x < 1
7) 2 . x - ( -17 ) = 15 18) | x | < 3
8) | x - 2 | = 3 19) ( x - 3 ) . ( x - 5 ) < 0
9) | x - 3 | - 7 = 13 20) 2 . x2 - 3 = 29
10) 72 - 3 . | x + 1 | = 9 21) -6 . x - ( -7) = 25
11) 17 - ( 43 - | x | ) = 45 22) 46 =- ( x - 11 ) = -48
Câu 1:
a) -8 + 5
b) -6 - 10
c) (-50) . (-9)
d) (-45) : 9
e) 24 . 125 + 24 . 75
g) 42 - 7 . 25
h) (5-7) . 11
i) (-3 - 12) : (-5)
k) 3 . (-4)^2 + 2 . (-5)
l) 125 . (-15) . 8
Tính giá trị biểu thức
A= 3.55+2.54+2.53+4.52+1
B=(1007+257_ 107) : 57
C=(11.322.37_915):(2.314)2
Tính nhanh
a) \(\dfrac{-3}{7}+\dfrac{15}{26}-\left(\dfrac{2}{13}-\dfrac{3}{7}\right)\)
b) \(2.\dfrac{3}{7}+\left(\dfrac{2}{9}-1\dfrac{3}{7}\right)-\dfrac{5}{3}:\dfrac{1}{9}\)
c) \(\dfrac{-11}{23}.\dfrac{6}{7}+\dfrac{8}{7}.\dfrac{-11}{23}-\dfrac{1}{23}\)
d) \(\left(\dfrac{377}{-231}-\dfrac{123}{89}+\dfrac{34}{791}\right).\left(\dfrac{1}{6}-\dfrac{1}{8}-\dfrac{1}{24}\right)\)