Piglets food

In the morning, Christopher puts out 7 3/5 pounds of food for the piglets on his farm.
In the evening, he puts out another 6 4/5 pounds. How much food does Christopher put out in all?

Correct answer:

x =  14 ²⁄₅ = 72/5 lb

Step-by-step explanation:

$$\begin{gathered} a=7\frac{3}{5}=7+\frac{3}{5}=\frac{7\cdot 5+3}{5}=\frac{35+3}{5}=\frac{38}{5}=7.6 \\ b=6\frac{4}{5}=6+\frac{4}{5}=\frac{6\cdot 5+4}{5}=\frac{30+4}{5}=\frac{34}{5}=6.8 \\ x=a+b=\frac{38}{5}+\frac{34}{5}=\frac{38+34}{5}=\frac{72}{5}=\frac{72}{5}\text{lb}=14\frac{2}{5}\text{lb}=14.4\text{lb} \end{gathered}$$

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