1,Tính
A, 14/7 + 5/9 + 4/9 - 2
B, 31/25 + ( 15/16 - 6/15 ) + 1/16
C, 23/28 - ( 23/28 - 1/3 ) +2/3
D, 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90
Tính
1, 14/7 + 5/9 + 4/9 - 2
2, 31/25 + ( 15/16 - 6/15 ) + 2/3
3, 23/28 - ( 23/28 - 1/3 ) + 2/3
4, 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90
Bài 1: Tính một cách hợp lí:
1) 2155 - ( 174 + 2155 ) + ( -68 + 174 ) 7) -1911 - ( 1234 - 1911 )
2) -25 . 72 + 25 . 21 - 49 . 25 8) 156 . 72 + 28 . 156
3) 35 . ( 14 - 23 ) - 23 . ( 14 - 35 ) 9) 32. ( -39 ) + 16 . ( -22 )
4) 8154 - ( 674 + 8154 ) + ( -98 + 674 ) 10) -1945 - ( 567 - 1945 )
5) -25 . 21 + 25 . 72 + 49 . 25 11) 184 . 33 + 67 . 184
6) 27 . ( 13 - 16 ) - 16 . ( 13 - 27) 12) 44 . ( -36 ) + 22 . ( -28 )
a, -13/30 + 11/20 - 7/15
b, -5 /72 : ( 3/8 . 7/9 )
c, -23/25 .10/17 + -23/25 . 3/13 + -27/25
BT1: Tìm x, biết
2)\(2+\dfrac{5}{7}+\left(\dfrac{\dfrac{3}{19}+\dfrac{3}{23}-\dfrac{3}{28}}{\dfrac{5}{19}+\dfrac{5}{23}-\dfrac{5}{28}}\right).x=\dfrac{20}{7}\)
( -1/2 )^2 : ( -1/4 ) - 2 . ( -1/2 )^3 + ( 25 - 23 )^2 =
25^10 . (1/5)^20 + ( -3/4 )^8 . ( -4/3)^8 - 2016^0
So sánh các cặp phân số sau
\(\dfrac{23}{28}\) và \(\dfrac{24}{27}\)
\(\dfrac{12}{25}\) và \(\dfrac{25}{49}\)
\(\dfrac{28}{154}\) và \(\dfrac{57}{308}\)
(-50+19+143)-(-79+25+48)
(-25)(75-45)-75(45-25)
(-37-17).(-9)+35.(-9-11)
(187-23)-(20-180)
512.(2-128)-128.(-512)
17.(-25)+25.21
Giải rõ ra nha ! Mình cần gấp !
Tính tổng :
a) ( -125 ) + 100 + 80 + 125 + 20
b) 27 + 55 + (-17) + ( -55)
c) (-92) + (-251) + (-8) +251
d) (-31 ) + (-95) + 131 + (-5)
e) ( 187 - 23) - (20 -180)
g) (-50 + 19 + 143 ) - (- 79 + 25 + 48)
1 . Tính nhanh
a/ 15 . ( 27 + 18 + 6 ) + 15 . ( 23 + 12 )
b/ 14 . 35 . 5 + 10 . 25 .7 + 20 . 70
c/ 53 . ( 51 + 4 ) + 53 . ( 49 + 96 ) + 53
d/ 46 . ( 27 + 75 ) + 8 . ( 58 + 25 ) . 2