Question

b1 :tính

a) 101 - 102 - (-103) - 104 - (-105) - 106 - (-107) - 108 - 109

b) ( a-1 ) - ( a-3 )

c) (2+b) - ( b+1)

Answer 1

ý a dễ r` k làm nữa, lm ý b, c thui nha!

b) (a-1) - (a - 3) = a - 1 - a + 3

= (a - a)+ (- 1 + 3) = 0 + 2 = 2

c) ( 2 + b) - (b + 1)

= 2 + b - b - 1 = ( b - b) + ( 2 - 1)

= 0 + 1 = 1

Answer 2

a) 101-102+103-104+105-106+107-108-109

=(101-102)+(103-104)+(105-106)+(107-108)-109

=(-1)-1-1-1-109

=(-4)-109

=-113

b) (a-1)-(a-3)

=a-1-a+3

=(a-a)+(-1+3)

=0+2

=2

c) (2+b)-b-1

=(b-b)+(2-1)

=0+1

=1