Bài 1: Tính bằng 2 cách a, (10-3/11+1/2) – (4+5/11-3/2) – (5-19/21+5/2) TÍNH BẰNG 2 CÁCH NHA, TÍNH HỢP LÍ CHO CTLHN LUÔN

Đáp án:

Giải thích các bước giải:

Cách 1 :

(10 – $\frac{3}{11}$ + $\frac{1}{2}$) – (4 + $\frac{5}{11}$ – $\frac{3}{2}$ ) – (5 – $\frac{19}{21}$ + $\frac{5}{2}$)

= $\frac{225}{22}$ – $\frac{65}{22}$ – $\frac{277}{42}$ 

= $\frac{313}{462}$ 

Cách 2 :

(10 – $\frac{3}{11}$ + $\frac{1}{2}$) – (4 + $\frac{5}{11}$ – $\frac{3}{2}$ ) – (5 – $\frac{19}{21}$ + $\frac{5}{2}$)

= 10 – $\frac{3}{11}$ + $\frac{1}{2}$ – 4 – $\frac{5}{11}$ + $\frac{3}{2}$ – 5 + $\frac{19}{21}$ – $\frac{5}{2}$

= ( 10 – 4 – 5 ) + ( $\frac{-3}{11}$ – $\frac{5}{11}$ ) + ( $\frac{1}{2}$ + $\frac{3}{2}$ – $\frac{5}{2}$ ) + $\frac{19}{21}$ 

= 1 + $\frac{-8}{11}$ + $\frac{-1}{2}$ + $\frac{19}{21}$ 

= $\frac{462}{462}$ + $\frac{-336}{462}$ + $\frac{-231}{462}$ + $\frac{418}{462}$ 

= $\frac{313}{462}$