Question

1:tính nhanh

a) (325-47)+(175-53)

b) (756-217)-(183-44)

2: chứng minh:

a) (a-b)+(c-d) = (a+c) - (b+d)

b) (a-b)-(c-d) = (a+d) - (b+c)

c) - (-a+c-d)-(c-a+d)=0

d) -(a+b-c+d)+(a-b-c-d) =0

 

 

 

Answer 1

(325 - 47) + (175 - 53)

=325 - 47 + 175 -53

=(325 + 175 ) - (47 + 53)

= 500 - 100

= 400
 

Answer 2

b)(756-217)-(183-44)

=756-217-183+44

=(756+44)-(217+183)

=800-400

=400

 

Answer 3

a)(325-47)+(175-43)

=325-47+175-53

=(325+175)-(47+53)

=500-100

=400