Question

4×6之分2+6×8分之2+8×10分之2+10×12分之2+12×14分之2=?

Answer 1

4×6分之2+6×8分之2+8×10分之2+10×12分之2+12×14分之2

=(1/4-1/6)+(1/6-1/8)+(1/8-1/10)+(1/10-1/12)+(1/12-1/14)

=1/4-1/6+1/6-1/8+1/8-1/10+1/10-1/12+1/12-1/14

=1/4-1/14

=14/56-4/56

=5/28