What is the number whose $\dfrac{7}{{10}}$ is 42?

Hint: We will assume the required number as $x$. We will try to write the mathematical equation using the relation given in the question. Then, solve the equation using general techniques to find the value of $x$.

Complete step by step answer:
We have to find the $\dfrac{7}{{10}}$ of a number that is 42. We will assume the number to be $x$.We will use the condition given in question and try to write the mathematical equation,
$ \Rightarrow \dfrac{7}{{10}} \times x = 42$
$ \Rightarrow \dfrac{{7x}}{{10}} = 42$
We will multiply both side by 10
$ \Rightarrow 7x = 42 \times 10$
We will divide both side by 7
$ \Rightarrow x = \dfrac{{42 \times 10}}{7}$
$ \therefore x = 60$

Hence, $\dfrac{7}{{10}}$ of 60 is 42.

Note: The best way to describe this is to imagine a number that has been cut into ten pieces. We need to figure out how many of each piece there are. $\dfrac{7}{{10}}$ refers to a score of seven out of ten or .7 as a decimal number. Some number 7 times makes 42, to find the number do $42 \div 7$ getting 6.