5 tính 3/5+4/7= 4/15+4/5= 5/6+3/8= 7 rút gọn rồi tính 2/5+3/15= 12/18+5/6= 17/10/2021 Bởi Kylie 5 tính 3/5+4/7= 4/15+4/5= 5/6+3/8= 7 rút gọn rồi tính 2/5+3/15= 12/18+5/6=
1/ $\dfrac35+\dfrac47=\dfrac{3×7}{5×7}+\dfrac{4×5}{7×5}=\dfrac{21}{35}+\dfrac{20}{35}=\dfrac{41}{35}$ Mẫu số chung: $15$ $\dfrac4{15}+\dfrac45=\dfrac4{15}+\dfrac{4\times3}{5\times3}=\dfrac4{15}+\dfrac{12}{15}=\dfrac{16}{15}$ $\dfrac56+\dfrac38=\dfrac{5\times8}{6\times8}+\dfrac{3\times6}{8\times6}=\dfrac{40}{48}+\dfrac{18}{48}=\dfrac{58}{48}=\dfrac{58:2}{48:2}=\dfrac{29}{24}$ 2/ $\dfrac25+\dfrac3{15}=\dfrac25+\dfrac15=\dfrac35$ $\dfrac{12}{18}+\dfrac56=\dfrac{12}{18}+\dfrac{15}{18}=\dfrac{27}{18}$ Bình luận
Tính `3/5+4/7` `=21/35+20/35` `=41/35` `4/15+4/5` `=4/15+12/15` `=16/15` `5/6+3/8` `=20/24+9/24` `=29/24` Rút gọn rồi tính `2/5+3/15` `=2/5+1/5` `=3/5` `12/18+5/6` `=4/6+5/6` `=3/2` Bình luận
1/ $\dfrac35+\dfrac47=\dfrac{3×7}{5×7}+\dfrac{4×5}{7×5}=\dfrac{21}{35}+\dfrac{20}{35}=\dfrac{41}{35}$
Mẫu số chung: $15$
$\dfrac4{15}+\dfrac45=\dfrac4{15}+\dfrac{4\times3}{5\times3}=\dfrac4{15}+\dfrac{12}{15}=\dfrac{16}{15}$
$\dfrac56+\dfrac38=\dfrac{5\times8}{6\times8}+\dfrac{3\times6}{8\times6}=\dfrac{40}{48}+\dfrac{18}{48}=\dfrac{58}{48}=\dfrac{58:2}{48:2}=\dfrac{29}{24}$
2/ $\dfrac25+\dfrac3{15}=\dfrac25+\dfrac15=\dfrac35$
$\dfrac{12}{18}+\dfrac56=\dfrac{12}{18}+\dfrac{15}{18}=\dfrac{27}{18}$
Tính
`3/5+4/7`
`=21/35+20/35`
`=41/35`
`4/15+4/5`
`=4/15+12/15`
`=16/15`
`5/6+3/8`
`=20/24+9/24`
`=29/24`
Rút gọn rồi tính
`2/5+3/15`
`=2/5+1/5`
`=3/5`
`12/18+5/6`
`=4/6+5/6`
`=3/2`