c)3+4/5 d)5+6/7 (lưu ý:tính nha phân số ý)
2 câu trả lời
`c)`
`3 + 4/5= 3/1 + 4/5 = (3xx5)/(1xx5) + (4xx1)/(5xx1) =15/5 + 4/5=(15+4)/5=19/5`
`d)`
`5 + 6/7 = (5xx7)/(1xx7) + (6xx1)/(7xx1) = 35/7 + 6/7= (35+7)/7 =42/7 =6`
`c)`
`3 + 4/5= 3/1 + 4/5 = (3xx5)/(1xx5) + (4xx1)/(5xx1) =15/5 + 4/5=(15+4)/5=19/5`
`d)`
`5 + 6/7 = (5xx7)/(1xx7) + (6xx1)/(7xx1) = 35/7 + 6/7= (35+7)/7 =42/7 =6`