2 phần 15 + ( 5 phần 9 + -6 phần9) (-1 phần 5 + 3 phần 12) +3 phần 4
2 câu trả lời
$\text{Bạn tham khảo ạ sai bảo mình để mình sửa}$
a, $\dfrac{2}{15}$ + ($\dfrac{5}{9}$ + $\dfrac{-6}{9}$)
= $\dfrac{2}{15}$ + $\dfrac{-1}{9}$
= $\dfrac{6}{45}$ + $\dfrac{-5}{45}$
= $\dfrac{1}{45}$
b, ($\dfrac{-1}{5}$ + $\dfrac{3}{12}$) + $\dfrac{3}{4}$
= ($\dfrac{-12}{60}$ + $\dfrac{15}{60}$) + $\dfrac{3}{4}$
= $\dfrac{3}{60 }$ + $\dfrac{3}{4}$
= $\dfrac{1}{20}$ + $\dfrac{15}{20}$
= $\dfrac{16}{20}$ = $\dfrac{4}{5}$
Đáp án+Giải thích các bước giải:
$\dfrac{2}{15}$ + $(\dfrac{5}{9}$ + $\dfrac{-6}{9})$
= $\dfrac{2}{15}$ + $(\dfrac{5 +(-6)}{9})$
= $\dfrac{2}{15}$ - $\dfrac{1}{9}$
= $\dfrac{18}{45}$ - $\dfrac{15}{45}$
= $\dfrac{18 - 15}{45}$
= $\dfrac{3}{45}$ = $\dfrac{1}{15}$
______________________________________________
$(\dfrac{-1}{5}$ + $\dfrac{3}{12})$ + $\dfrac{3}{4}$
= $(\dfrac{-12}{60}$ + $\dfrac{15}{60})$ + $\dfrac{3}{4}$
= $(\dfrac{-12 + 15}{60})$ + $\dfrac{3}{4}$
= $\dfrac{3}{60}$ + $\dfrac{3}{4}$
= $\dfrac{1}{20}$ + $\dfrac{3}{4}$
= $\dfrac{1}{20}$ + $\dfrac{15}{20}$
= $\dfrac{1 + 15}{20}$
= $\dfrac{16}{20}$ = $\dfrac{4}{5}$
