Question

What is $\frac{5}{8}$ as a decimal ?

Answer 1

You would have been told the shortcut way of just dividing $8$ into $5.$ Easy if a calculator. Sometimes not so if you have to do it manually.
What follows is just one method out of several.
There some fractions that it is advisable that you commit their decimal equivalents to memory. This is one of them.
Known: $\frac{1}{8}=0.125$
So, $\frac{5}{8}=5\times 0.125$
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Rather than worry about the decimal when you multiply think of $0.125,$ consider it as $\frac{125}{1000}$ or the same thing $125\times \frac{1}{1000}.$ They all have the same intrinsic value.
Step 1
Just for a moment do not think about the $\times \frac{1}{1000}$
Write as:
$125$
$5\leftarrow$ Multiply
$--$
$625$
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Step 2
Now we must think about the $\times \frac{1}{1000}$ giving:
$125$
$5\leftarrow$ Multiply
$--$
$625\leftarrow 625\times \frac{1}{1000}=0.625$