Tính nhanh
a) -37+54+(-70)+(-163)+246
b)-359+181+(-123)+350+(-172)
c)-69+53+46+(-94)+(-14)+78
d)13-12+11+10-9+8-7-6+5-4+3+2-1
Tính nhanh a) -37+54+(-70)+(-163)+246 b)-359+181+(-123)+350+(-172) c)-69+53+46+(-94)+(-14)+78 d)13-12+11+10-9+8-7-6+5-4+3+2-1
By Lydia
`a) -37+54+(-70)+(-163)+246`
`=[(-37)+(-163)]+(56+246)+(-70)`
` =-200 +300+(-70)`
`=100+(-70)`
` =30`
`b)-359+181+(-123)+350+(-172)`
`=[-359+181+(-172)]+(-123)+350`
`=-350+(-123)+350`
`=(-350+350)+(-123)`
` =0-123`
` =-123`
`c)-69+53+46+(-94)+(-14)+78`
` =-69+[53+46+(-94)+(-14)]`
`=-69+69`
`=0`
`d)13-12+11+10-9+8-7-6+5-4+3+2-1`
`=(13-12)+11+(10-9)+(8-7-6+5)+(-4+3+2-1)`
`=(13-12)+11+(10-9)+(8-7-6+5)+(-4+3+2-1)`
`=1+11+1+0`
`=13`
`@dongnguyen2211`
`-37+54+(-70)+(-163)+246`
`= ((-37)+(-163))+(54+246)+(-70)`
`= -200 + 300 + (-70)`
`= 100 + (-70)`
`= 30`
`-359+181+(-123)+350+(-172)`
`= (-359+181+(-172)) + (-123)+350`
`= -350 + (-123)+350`
`= (-350 + 350) + (-123)`
`= 0 – 123`
`= -123`
`-69+53+46+(-94)+(-14)+78`
`= -69 + (53+46+(-94)+(-14)+78)`
`= -69 + 69`
`= 0`
`13-12+11+10-9+8-7-6+5-4+3+2-1`
`= (13-12)+11+(10-9)+(8-7-6+5)+(-4+3+2-1)`
`= 1 + 11 + 1 + 0 + 0`
`= 13`
(Chúc bạn hok tốt ạ)