Hint: We should use the concept of elementary Mathematics here in this question. Simple addition and subtraction is what elementary Mathematics includes. If a person’s present age is given and it is asked to find his/her age before and after some years then we simply have to subtract and add the number of years to the age to get the required answer.
Complete step-by-step answer:
Addition along with subtraction, multiplication and division are the four basic operations of arithmetic. Addition operation is represented by the sign ‘$+$’ (read as ‘plus’). The addition of two numbers gives the total amount of those values combined. Subtraction is also a basic operation of arithmetic and is represented by the sign ‘$-$’ (read as ‘minus’). The subtraction is the operation of removing objects from a collection. The result of subtraction is called difference.
Now, it is given that the Meena’s present age is ‘$k$’ years and we have to find her age 2 years after and 7 years ago. We need to add 2 to her present age to get her age after 2 years and we need to subtract 7 from her present age to get her age 7 years ago.
Hence, her age after 2 years is ‘$k+2$’ years and her age before 7 years is ‘$k-7$’ years.
Note: In this question basic mathematical operations particularly addition and subtraction is used. So, it is necessary to understand these terms. We can quickly solve this problem if we are able to perform these operations quickly.