Bài 1 :
a, 2013 - 79 -1013 - 21
= (2013 -1013 ) + (-79 -21 )
=1000 - 100
=900
b, 135 - 591 -409 +437
= ( 135 + 437 ) +(-591 -409 )
= 572 -1000
= -428
c, -46 - 135 +35 +146
= 100 -100
= 0
a) 2013-79-1013-21
=(2013-1013)-(-79-21)
=1000-100
=900
b) 135-591-409+437
=(135+437)-(-591-409)
= 572-1000
= -428
c) -46-135+35+146
= (-46+146)+(-135+35)
=100+(-100)
=0