How do you write $8\dfrac{7}{8}$ as an improper fraction?

Hint: Fraction where the numerator is greater than the denominator is called improper fraction.
Fraction, where the numerator is smaller than the denominator, is called a proper fraction.
Whole numbers are numbers starting from 0 to infinity.
A mixed fraction is a number consisting of a whole number and a proper fraction.
Here 8 is the whole number, the numerator is 7 and the denominator is 8.
As 7 is smaller than 8, fraction $\dfrac{7}{8}$ is a proper fraction.

Complete step by step solution:
Multiply the whole number by the denominator
$ \Rightarrow $$8 \times 8 = 64$
Add the product of a whole number and denominator to numerator i.e.,
$ \Rightarrow 64 + 7$
$ \Rightarrow 71$
Now, put the same denominator 8 and make a fraction where the numerator will be 71
$ \Rightarrow \dfrac{{71}}{8}$
Here, numerator is 71 and denominator is 8.
71 is greater than denominator 8 which makes the fraction $\dfrac{{71}}{8}$ as an improper fraction.

Thus, $8\dfrac{7}{8}$ as improper fraction is $\dfrac{{71}}{8}$.

Additional information:
Remember the steps to convert a mixed fraction into an improper fraction.
Step 1: Multiply the whole number by the denominator
Step 2: Add the product of a whole number and denominator to the numerator. This will give the numerator of the improper fractions.
Step 3: Put the same denominator (denominator which is given in question) for the numerator obtained.
Step 4: Hence the required improper fraction is obtained.

Note: Always specify the mixed fractions into the whole number, numerator, and denominator to make it easier to solve.
Don’t be confused between numerator and denominator.
Keep the steps to convert a mixed fraction into an improper fraction in mind while solving this type of question.