Question

[Milô]

Bài 1: Tính

  a) 2,4/9 +  6,7/11 + 7,5/9 +13,4/11        b)3/4 + 1/2 x 12/5 - 1,1/2       

2,4/9 ; 6,7/11 ; 7,5/9 ; 13,4/11 ; 1,1/2 là hỗn số     

Answer 1

[HT.Phong (9A5)]

a) \(2\dfrac{4}{9}+6\dfrac{7}{11}+7\dfrac{5}{9}+13\dfrac{4}{11}\)

\(=2+\dfrac{4}{9}+6+\dfrac{7}{11}+7+\dfrac{5}{9}+13+\dfrac{4}{11}\)

\(=\left(2+6+7+13\right)+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)+\left(\dfrac{7}{11}+\dfrac{4}{11}\right)\)

\(=28+1+1\)

\(=30\)

b) \(\dfrac{3}{4}+\dfrac{1}{2}\times\dfrac{12}{5}-1\dfrac{1}{2}\)

\(=\dfrac{3}{4}+\dfrac{1}{2}-1-\dfrac{1}{2}\)

\(=\dfrac{3}{4}-1\)

\(=\dfrac{3}{4}-\dfrac{4}{4}\)

\(=-\dfrac{1}{4}\)