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8 votes
8 votes
What is 2 2/5 - 3 1/2

User ECallpani
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1 Answer

16 votes
16 votes

\begin{gathered} 2\cdot(2)/(5)-3\cdot(1)/(2)=((2\cdot5)+2)/(5)-((3\cdot2)+1)/(2) \\ =(10+2)/(5)-(7)/(2) \\ =(12)/(5)-(7)/(2) \end{gathered}
\begin{gathered} \text{ Now, we remember that } \\ (a)/(b)-(c)/(d)=((a\cdot d)-(b\cdot c))/(b\cdot d) \end{gathered}
\begin{gathered} \text{ Thus we get } \\ (12)/(5)-(7)/(2)=((12\cdot2)-(5\cdot7))/(5\cdot2) \\ =(24-35)/(10) \\ =-(11)/(10) \end{gathered}
\begin{gathered} \text{ So, we finally have} \\ 2\cdot(2)/(5)-3\cdot(1)/(2)=(-11)/(10) \end{gathered}

User DavidScherer
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