Question

thực hiện phép tính sau:

1/6+1/12+1/20+1/30+1/42+1/56

Answer 1

 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 
=1/(2.3)+1/(3.4)+1/(4.5) + 1/(5.6)+ 1/(6.7)+1/(7.8)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5.+1/5-1/6+1/6-1/7+1/7-1/8 
=1-1/8 
=7/8

Answer 2

= 1/(2.3) + 1/(3.4) + 1/(4.5) + 1/(5.6) + 1/(6.7) + 1/(7.8)

= 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 +  1/6 - 1/7 + 1/7 - 1/8

= 1/2 - 1/8

= 3/8