Algebraic expressions With example Problems and Interactive Exercises

Use the adhering to examples and interactive practice to learn around Writing Algebraic Expressions.

You are watching: Fifteen more than half a number is 9


Problem: Ms. Jensen likes to divide her class into teams of 2. Usage mathematical icons to stand for all the students in she class.

Solution: Let g represent the number of groups in Ms. Jensen"s class.

Then 2 · g, or 2g have the right to represent "g groups of 2 students".

In the trouble above, the change g represents the number of groups in Ms. Jensen"s class. A variable is a symbol used to stand for a number in one expression or one equation. The value of this number can vary (change). Let"s look at an instance in i m sorry we use a variable.

Example 1: Write each phrase as a mathematics expression.

Phrase Expression the amount of nine and also eight 9 + 8 the sum of nine and a number x 9 + x

The expression 9 + 8 represents a single number (17). This expression is a numerical expression, (also called an arithmetic expression). The expression 9 + x represents a worth that have the right to change. If x is 2, climate the expression 9 + x has a value of 11. If x is 6, then the expression has actually a value of 15. So 9 + x is an algebraic expression. In the next few examples, we will be working specifically with algebraic expressions.

Example 2: Write each expression as one algebraic expression.

Phrase Expression nine enhanced by a number x 9 + x fourteen reduced by a number p 14 - ns seven less than a number t t - 7 the product that 9 and a number n 9 · n   or   9n thirty-two divided by a number y 32 ÷ y   or   

In example 2, each algebraic expression contained one number, one operation and also one variable. Let"s watch at an instance in which the expression consists of an ext than one number and/or operation.

Example 3: Write each phrase as an algebraic expression utilizing the variable n.

Phrase Expression five much more than double a number 2n + 5 the product that a number and also 6 6n seven separated by double a number 7 ÷ 2n   or   
3 times a number lessened by 11 3n - 11

Example 4: A little company has $1000 to distribute to the employees as a bonus. Just how much money will certainly each employee get?

Solution: Let e represent the number of employees in the company. The lot of money every employee will acquire is stood for by the adhering to algebraic expression:


Example 5: An electrician dues $45 every hour and spends $20 a work on gasoline. Create an algebraic expression to represent his revenue for one day.

Solution: Let x stand for the number of hours the electrician functions in one day. The electrician"s earnings deserve to be represented by the following algebraic expression:

Solution: 45x - 20

Summary: A variable is a symbol used to represent a number in an expression or one equation. The worth of this number can change. An algebraic expression is a mathematics expression that consists of variables, numbers and also operations. The worth of this expression have the right to change.


Directions: select the algebraic expression that properly represents the phrase provided. Pick your prize by clicking on its button. Feedback to her answer is listed in the outcomes BOX. If you make a mistake, pick a various button.

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1.  Fifteen less than twice a number     15 - 2x2x + 152x - 15None the the above.


2.  Three times a number, enhanced by seventeen     3(a + 17)3a + 17(17 + 3)aNone the the above.


3.  The product of nine and a number, reduced by six     9(m - 6)6(9 - m)9m - 6None the the above.


4.  Thirty divided by 7 times a number     30 + 7n
30(7n) none of the above.   outcomes BOX: 5.  Jenny earns $30 a work working part time in ~ a supermarket. Compose an algebraic expression to stand for the lot of money she will earn in d days.     30d
30 + d none of the above   results BOX: