# EVALUATING REAL WORLD EXPRESSIONS

## About "Evaluating real world expressions"

Evaluating real world expressions :

An algebraic expression is an expression that contains one or more variables and may also contain operation symbols, such as + or -

We can solve many real world problems by evaluating algebraic expressions.

## Evaluating real world expressions - Examples

Example 1 :

A scientist measures the air temperature in Death Valley, California, and records 50 °C. The expression 1.8c + 32 gives the temperature in degrees Fahrenheit for a given temperature in degrees Celsius c. Find the temperature in degrees Fahrenheit that is equivalent to 50 °C.

Solution :

Step 1 :

Fromm the given information, we have

c  =  50 °C

Step 2 :

Plug the value into the expression.

1.8c + 32

Plug 50 for c

1.8(50) + 32

Multiply

90 + 32

122

Hence, 122 °F is equivalent to 50 °C.

Example 2 :

The expression 6x² gives the surface area of a cube, where x is the length of one side of the cube. Find the surface area of a cube with a side length of 2 meters.

Solution :

Step 1 :

Fromm the given information, we have

x  =  2

Step 2 :

Plug the value into the expression which represents surface area of the cube.

6x²

Plug 2 for x

6(2)²

Evaluate exponents

6(4)

Multiply

24

Hence, the surface area of the cube 24 m²

Example 3 :

The expression x³ gives the volume of a cube, where x is the length of one side of the cube. Find the volume of a cube with a side length of 2 meters.

Solution :

Step 1 :

Fromm the given information, we have

x  =  2

Step 2 :

Plug the value into the expression.

x³

Plug 2 for x

(2)³

Evaluate exponents

8

Hence, the volume of the cube 8 m³

Example 4 :

The expression 60m gives the number of seconds in m minutes. How many seconds are there in 7 minutes?

Solution :

Step 1 :

Fromm the given information, we have

m  =  7

Step 2 :

Plug the value into the expression.

60m

Plug 7 for m

60(7)

Multiply

420

Hence, there are 420 seconds in 7 minutes.

After having gone through the stuff given above, we hope that the students would have understood "How to evaluate real world expressions".

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WORD PROBLEMS

HCF and LCM  word problems

Word problems on simple equations

Word problems on linear equations

Algebra word problems

Word problems on trains

Area and perimeter word problems

Word problems on direct variation and inverse variation

Word problems on unit price

Word problems on unit rate

Word problems on comparing rates

Converting customary units word problems

Converting metric units word problems

Word problems on simple interest

Word problems on compound interest

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Complementary and supplementary angles word problems

Double facts word problems

Trigonometry word problems

Percentage word problems

Profit and loss word problems

Markup and markdown word problems

Decimal word problems

Word problems on fractions

Word problems on mixed fractrions

One step equation word problems

Linear inequalities word problems

Ratio and proportion word problems

Time and work word problems

Word problems on sets and venn diagrams

Word problems on ages

Pythagorean theorem word problems

Percent of a number word problems

Word problems on constant speed

Word problems on average speed

Word problems on sum of the angles of a triangle is 180 degree

OTHER TOPICS

Profit and loss shortcuts

Percentage shortcuts

Times table shortcuts

Time, speed and distance shortcuts

Ratio and proportion shortcuts

Domain and range of rational functions

Domain and range of rational functions with holes

Graphing rational functions

Graphing rational functions with holes

Converting repeating decimals in to fractions

Decimal representation of rational numbers

Finding square root using long division

L.C.M method to solve time and work problems

Translating the word problems in to algebraic expressions

Remainder when 2 power 256 is divided by 17

Remainder when 17 power 23 is divided by 16

Sum of all three digit numbers divisible by 6

Sum of all three digit numbers divisible by 7

Sum of all three digit numbers divisible by 8

Sum of all three digit numbers formed using 1, 3, 4

Sum of all three four digit numbers formed with non zero digits

Sum of all three four digit numbers formed using 0, 1, 2, 3

Sum of all three four digit numbers formed using 1, 2, 5, 6