The Numerical Value in Algebraic Expressions

For example:

If we want to give $X$ a value of $3$ in the expressions below, we will obtain the following:

a) $X+5-X=3+5-3=5$

b)$-10+X\times\left(\frac{4}{X}\right)=-10+3\times\left(\frac{4}{3}\right)=-10+3\times\frac{4}{3}=-10+4=-6$

c) $X+Y-5=3+Y-5$

If you are interested in this article, you may also be interested in the following articles:

• Unknowns and algebraic expressions.
• Equivalent Expressions / Equivalent Algebraic Expressions
• Multiplication of algebraic expressions
• Simplification of elements / Simplification of similar elements
• Table of values

On the Tutorela blog, you will find a variety of other useful articles about mathematics!

Find the numerical value of the following expression if $X=4$:

$8+X+8X+12:3$

Solution:

We replace $X$ with the number $4$ and solve.

$8+4+8\cdot4+12:3=48$

Answer:

$48$

Find the numerical value of the following expression if $X=2.5$:

$\frac{(X+X)3}{3}$

Solution

First, we substitute $2.5$ in the place of $X$ and then perform the various operations.

$\frac{(2.5+2.5)3}{3}=5$

Answer:

$5$

Find the numerical value of the following expression given that $X=10$ and $Y=7$:

$X²+Y²+1000$

Solution

We simply replace $X$ and $Y$ with the given numbers and solve.

$100+49+1000$

$10²+7²+1000=1149$

Answer:

$1149$

Find the numerical value of the following expression if $X=12$ and $Y=9$:

$\frac{X}{6}+\frac{Y}{6}$

Solution

We substitute the given numbers for $X$ and $Y$ and then solve.

$\frac{12}{6}+\frac{9}{6}$

$2+\frac{3}{2}$

Answer:

$2\frac{3}{2}$

Find the numerical value of the following expression if $X=4$, $Y=8$, and $Z=2$:

$X\cdot\frac{Y}{Z}+X²+\frac{Y}{2}+200$

Solution

We replace $X,Y$ and $Y$ with the given numbers and solve.

$4\cdot\frac{8}{2}+4²+\frac{8}{2}+200$

$4\cdot4+16+4+200$

$4\cdot4+16+4+200=236$

Answer:

$236$

What are algebraic expressions?

An algebraic expression is a combination of constant numbers (or 'integers'), unknown variables represented by letters, and basic operations. For example:

a) $x+3$

b) $2x+y$

c) $a^2 -6a+1$

d) $(x+1)(x-2)$

e) $m^2 -n^2 -1$

To calculate the numerical value of an algebraic expression or a polynomial, we must assign each variable with a value. Then we substitute these values into the expression and perform all the operations indicated. The result obtained will be the numerical value of the expression for the assigned values of the variables.

The numerical value of an algebraic expression is the value to which the expression is reduced once we have assigned all of the variables with a value and performed the operations.

If $x = 2$, then what is the value of $x^2 – 3x + 7$?

Solution

Replace x with its assigned value and perform the operations.

$(2)^2 -3(2)+7 = 4 – 6 + 7 = 11 - 6 = 5$

Given that $m = 4$ and $n = 10$, find the value of $(m+3)(n-6)$.

Solution

$(4 + 3)(10 - 6) = (7)(4) = 28$

Algebraic expressions are used to represent unknown quantities in a given problem, but once we know these values it is no longer necessary to represent them using algebraic expressions. The numerical value indicates the quantity that is represented by the expression.

Are there any geometry topics that you don't fully understand? Well, if the answer is 'yes', then don't worry—it's normal! There are topics that you will learn easily and there will be others that take you longer to grasp.

Important: Try not to fall behind with the subject material, as the pace at which most students learn mathematics is very fast. The problem is that many topics are based on what has been taught before, meaning that if you try to move on to a new subject while your knowledge of the previous one still has holes in it, you will likely struggle with it.

• You find it difficult to maintain your concentration in class, as you find it hard to understand the teacher.
• You have difficulty doing your homework.
• You have received a very low grade on an exam.

• You can ask a classmate to explain what you don't understand.
• Ask your mathematics teacher to help you with the topic you don't understand.
• You can hire a private tutor to explain the topic you don't understand from the beginning.