TÍNH NHANH
a) 3/16 + 4/15 + 5/16 + 1/15
b) 6/7 x 8/15 x 7/6 x 15/16
c) 19/20 x 13/21 + 9/20 x 8/21
d) (1+ 10/15 ) x (1+ 1/16 ) x ( 1+ 1/17 ) x ( 1+ 1/18 )
MINK ĐANG CẦN GẤP
15/5 x 15/30 :20/31=??
Tìm x, biết:
a) x - 2 = \(\dfrac{7}{15}\)
b) \(\dfrac{9}{20}\) + x = \(\dfrac{2}{5}\) + \(\dfrac{3}{20}\)
-15 + 20 x 100 = ? x ? = ? x 2 = ?
(x+5)+(x+10)+(x+15)+(x+20)=74
(x+5) +(x+10) +(x+15)+(x+20)=74
( x + 5 ) + ( x + 10 ) + ( x + 15 ) + ( x + 20 ) = 74
(x+5)+(x+10)+(x+15)+(x+20)=74
[ x +5 ] + [ x + 10 ] + [x +15 ] + [ x + 20 ] = 74
(x*5)+(x*10)+(X*15)+(x*20)=74