Question

1 1/2 +7 4/5. one whole number ,one over 2 plus 7 whole number 4/5

Answer 1

Given the following sum:

$1\frac{1}{2}+7\frac{4}{5}$

For each term we have (from mixed numbers to fractions):

$\begin{gathered} 1\frac{1}{2}=\frac{1\cdot2+1}{2}=\frac{2+1}{2}=\frac{3}{2} \\ \\ 7\frac{4}{5}=\frac{7\cdot5+4}{5}=\frac{35+4}{5}=\frac{39}{5} \end{gathered}$

Then:

$1\frac{1}{2}+7\frac{4}{5}=\frac{3}{2}+\frac{39}{5}$

Using the cross product method:

$\begin{gathered} \frac{3}{2}+\frac{39}{5}=\frac{3\cdot5+39\cdot2}{2\cdot5}=\frac{15+78}{10}=\frac{93}{10} \\ \\ \therefore1\frac{1}{2}+7\frac{4}{5}=\frac{93}{10} \end{gathered}$

In mixed form:

$1\frac{1}{2}+7\frac{4}{5}=9\frac{3}{10}$