hoàn thành các phép tính sau
a) tính tổng \(2\dfrac{3}{4}\) +\(5\dfrac{7}{9}\)
cách 1
\(2\dfrac{3}{4}+5\dfrac{7}{9}=\dfrac{...}{4}+\dfrac{...}{9}\)
\(=\dfrac{99}{36}+\dfrac{...}{36}\)
\(=\dfrac{...}{36}=...\)
cách 2
\(2\dfrac{3}{4}+5\dfrac{7}{9}=2\dfrac{...}{36}+5\dfrac{...}{36}\)
=\(7\dfrac{...}{36}=8\dfrac{...}{36}\)
Cách 1
\(2\dfrac{3}{4}\)+ \(5\dfrac{7}{9}\)= \(\dfrac{11}{4}+\dfrac{47}{9}\)
= \(\dfrac{99}{36}+\dfrac{188}{36}\)
= \(\dfrac{287}{36}\)= 7,9722...
Cách 2
\(2\dfrac{3}{4}+5\dfrac{7}{8}=2\dfrac{55}{36}+5\dfrac{55}{36}\)
= \(7\dfrac{55}{36}=8\dfrac{19}{36}\)
Cách 1 mình làm nhầm bài đúng phải là
\(2\dfrac{3}{4}+5\dfrac{7}{9}=\dfrac{11}{4}+\dfrac{52}{9}=\dfrac{99}{36}+\dfrac{208}{36}\)
=\(\dfrac{307}{36}\)=8,527777778
