How can you add and subtract rational numbers on a calculator $3/4+5/6$?

Hint: In this question we have been given with two rational numbers which are in the form of a fraction. A rational number is a number which is a number which is terminating. Non terminating numbers are those whose decimals go on continuously. They are also called recurring numbers. The addition and subtraction of numbers depends on the calculator. In this question as an example, we will use the $\text{TI-84}$ calculator and also see how to solve it without a calculator.

Complete step by step solution:
We have term given to us as:
$ \dfrac{3}{4}+\dfrac{5}{6}$
Now the general way to solve these types of problems will be to take a common denominator by taking the lowest common multiple of both the denominators.
In the above problem, the lowest common multiple of $4$ and $6$ is $12$ therefore, we will multiply and divide the first term by $3$ and the second term by $2$.
$\Rightarrow \dfrac{3\times 3}{4\times 3}+\dfrac{5\times 2}{6\times 2}$
On simplifying, we get:
$\Rightarrow \dfrac{9}{12}+\dfrac{10}{12}$
Now since we have a common denominator, we can write the fraction as:
$\Rightarrow \dfrac{19}{12}$, since it cannot be simplified further, it is the required solution.
Now consider the same problem on a $\text{TI-84}$ calculator. The steps would be:
$1)$ open parenthesis by pressing $($
$2)$ type the numerator of the first fraction.
$3)$ put in $/$.
$4)$ type the denominator of the first fraction.
$5)$ close the parenthesis by pressing $)$
$6)$ put the addition or subtraction operator as $+$ or $-$.
$7)$ put the value of the second fraction by following steps $1$ to $5$.
$8)$ press $\left[ \text{ENTER} \right]$ button. Note that the solution will be in decimals.
$9)$ press $\left[ \text{MATH} \right]$ button then press $\left[ \text{ENTER} \right]$ twice to get the solution in a simplified fraction.

Note: It is to be noted that the method to solve multiplication and division is different in general mathematics but on a $\text{TI-84}$ calculator if the division or multiplication sign is put, the answer can be found. It is to be noted that the steps would vary from calculator to calculator.