Question

17+18+19+20+21+22+23

 

Answer 1

17 + 18 + 19 + 20 + 21 + 22 + 23

= (17 + 23) + (18 + 22) + (19 + 21) + 20

= 40 + 40 + 40 + 20

= 140 

Answer 2

17+18+19+20+21+22+23= (17+23)+?(18+22)+(19+21)+20= 40+40+40+40+20= 160+20+180

Answer 3

Đề bài: 17 + 18 + 19 + 20 + 21 + 22 + 23
Ta có:
( 17 + 23 ) + ( 18 + 22 ) + ( 19 + 21 ) + 20
= 40 + 40 + 40 + 20
= 140