Đáp án+Giải thích các bước giải:
Bài 1:
a) $\frac{4}{2}$ + $\frac{3}{7}$ + $\frac{1}{5}$ = $\frac{140}{70}$ + $\frac{30}{70}$ + $\frac{14}{70}$ =$\frac{140+30+14}{70}$ =$\frac{184}{70}$ =$\frac{92}{35}$
b) $\frac{9}{4}$ - $\frac{2}{3}$ + $\frac{1}{2}$ = $\frac{27}{12}$ - $\frac{8}{12}$ + $\frac{6}{12}$= $\frac{27-8+6}{12}$ =$\frac{25}{12}$
c) 6 + $\frac{8}{11}$ + $\frac{4}{5}$ = $\frac{330}{55}$ + $\frac{40}{55}$ +$\frac{44}{55}$ =$\frac{414}{55}$
d) $\frac{14}{9}$ + (2-$\frac{7}{6}$) = $\frac{28}{18}$ + ($\frac{36}{18}$ +$\frac{21}{18}$) =$\frac{28}{18}$+$\frac{57}{18}$= $\frac{85}{18}$
e) 7-($\frac{9}{12}$+ $\frac{2}{4}$)= $\frac{84}{12}$ -( $\frac{9}{12}$ + $\frac{6}{12}$)= $\frac{84}{12}$- $\frac{15}{12}$ =$\frac{69}{12}$= $\frac{23}{4}$
f) $\frac{12}{36}$ + $\frac{8}{5}$ +$\frac{9}{27}$ = $\frac{180}{540}$ + $\frac{864}{540}$ +$\frac{180}{540}$ =$\frac{180+864+180}{540}$ =$\frac{1224}{540}$ =$\frac{34}{15}$
Bài 2:
a) $\frac{4}{19}$ + $\frac{12}{23}$ +$\frac{15}{19}$ +$\frac{34}{23}$ = ($\frac{4}{19}$+$\frac{15}{19}$) + ( $\frac{12}{23}$+$\frac{34}{23}$)= 1+ $\frac{57}{23}$ =$\frac{80}{23}$
b) $\frac{5}{3}$ +$\frac{23}{8}$ =$\frac{40}{24}$ + $\frac{69}{24}$ =$\frac{109}{24}$
c) $\frac{14}{15}$+$\frac{11}{16}$ +$\frac{5}{16}$ +$\frac{1}{15}$= ($\frac{14}{15}$+$\frac{1}{15}$)+($\frac{11}{16}$ +$\frac{5}{16}$)= 1+1=2
d) $\frac{16}{7}$ +$\frac{4}{3}$ +$\frac{5}{7}$=($\frac{16}{7}$ + $\frac{5}{7}$) + $\frac{4}{3}$= $\frac{21}{7}$ + $\frac{4}{3}$= 3 + $\frac{28}{21}$= $\frac{13}{7}$
@Tuantuth23
#Kun~
*Cho mik xin ctlhn và 5 sao + 1 tim nhá, cảm ơn bạn nhiều :))
