Question

Tính nhanh

B = 3/4.8/9.15/16.....2499/2500

Answer 1

B = 3/4.8/9.15/16.....2499/2500

= 1.3/2^2 . 2.4/3^2 . 3.5/4^2 ..... 49.51/50^2

= 1.2.3.....49/1.2.3.....50 . 3.4.5....51/1.2.3.....50

= 1/50 . 51/2

= 51/100

Answer 2

                                                                               Giải

B = 3/4.8/9.15/16.....2499/2500

B=1.3/2^2 . 2.4/3^2 . 3.5/4^2 ..... 49.51/50^2

B=1.2.3.....49/2.3.4.....50 . 3.4.5.....51/2.3.4.....50

B=1/50 . 51/2 

B=51/100