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

2 bình luận về “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”

1. Giải đáp+Lời giải và giải thích chi tiết:

   a)-37+54+(-70)+(-163)+246

   =(54+246)+[(-37)+(-163)]+(-70)

   =300+(-200)+(-70)

   =300+[(-200)+(-70)]

   =300+(-270)

   =30

   b)-359+181+(-123)+350+(-172)

   =[(-359)+181]+[(-123)+(-172)]+350

   =(-178)+(-295)+350

   =[(-178)+(-295)]+350

   =(-473)+350

   =-123

   c)-69+53+46+(-94)+(-14)+78

   =-69+53+46+[(-94)+(-14)]+78

   =-69+53+46+(-108)+78

   =[(-69)+(-108)]+53+46+78

   =(-177)+53+46+78

   =[(-177)+53]+46+78

   =(-124)+46+78

   =[(-124)+46]+78

   =(-78)+78

   =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

   =1+21-1-13+1+5-1

   =(1-1+1-1)+(21-13+5)

   =0+13

   =13

   Trả lời
2. a)

   – 37 + 54 + ( – 70 ) + ( -163 ) + 246

   = [ – 37 + ( – 163 ) ] + ( 54 + 246 ) + ( – 70 )

   = – 200 + 300 + ( – 70 )

   = 100 + ( – 70 )

   = 30

   b)

   – 359 + 181 + ( – 123 ) + 350 + ( – 172 )

   = [ – 359 + 181 ] +  ( – 123 ) + 350 + ( – 172 )

   = – 178 + ( – 123 ) + 350 + ( -172 )

   = [ – 178 + ( -172 )] + ( – 123 ) + 350

   = – 350 + ( – 123 ) + 530

   = [ – 350 + 530 ] + ( – 123 )

   = 0 + ( – 123 )

   = – 123

   c)

   – 69 + 53 + 46 + ( – 94 ) + ( – 14 ) + 78

   = − 69 + 53 + 46 + [ ( − 94 ) + ( − 1 4 ) ] + 78

   = −69 + 53 + 46 + ( −108 ) + 78

   = [ ( −69 ) + ( − 108 ) ] + 53 + 46 + 78

   = ( − 177 ) + 53 + 46 + 78

   = [ ( − 177 ) + 53 ] + 46 + 78

   = ( − 124 ) + 46 + 78

   = [ ( − 124 ) + 46 ] + 78

   = ( − 78 ) + 78

   = 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

   = 1 + 2 1 − 1 − 13 + 1 + 5 − 1

   = ( 1 − 1 + 1 − 1 ) + ( 2 1 − 1 3 + 5 )

   = 0 + 13

   = 13

   @bingchilling

   Trả lời