Question

Tính nhanh:  A=4/3+7/6+11/10+16/15+22/21+29/28+37/36+46/45

Answer 1

A=4/3+7/6+11/10+16/15+22/21+29/28+37/36+46/45 

A = ( 1 + 1/3 ) + ( 1 + 1/6 ) + ( 1 + 1/10 ) + ( 1 + 1/15 ) + ( 1 + 1/21 ) + ( 1 + 1/28 ) + ( 1 + 1/36 ) + ( 1 + 1/45 )

A = ( 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 ) + - ( 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 )

A = 8 + 4/5

A = 44/5

Answer 2

A = 4/3 + 7/6 + 11/10 + 16/15 + 22/21 + 29/28 + 37/36 + 46/45

A = ( 1 + 1/3 ) + ( 1 + 1/6 ) + ( 1 + 1/10 ) + ( 1 + 1/15 ) + ( 1 + 1/21 ) + ( 1 + 1/28 ) + ( 1 + 1/36 ) + ( 1 + 1/45 )

A = ( 1 + 1 + 1 + ... + 1 ) - ( 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 )