WRITING AND EVALUATING EXPRESSIONS
About "Writing and evaluating expressions"
"Writing and evaluating expressions" is one of the important basic stuff of algebra in math.
Students who would like to learn solving word problems in math must study this basic stuff.
Writing expressions for the given verbal phrases
Let us see, how to write verbal phrase into expressions.
If there is any unknown value, in the given verbal phrase, replace it by some English alphabet.
Example 1
Example 2
Example 3
Writing expressions - Practice questions
To have better understanding on "writing expressions", let us look at some practice questions.
Question 1 :
Write the given verbal phrase into mathematical expression
"The sum of 5 times a number and 8"
Answer :
5x + 8
Let us look at the next question on "Writing expressions"
Question 2 :
Write the given verbal phrase into mathematical expression
"2 times the sum of 7 times a number and 4"
Answer :
2(7x + 4)
Let us look at the next question on "Writing expressions"
Question 3 :
Write the given verbal phrase into mathematical expression
"7 less than 4 times a number"
Answer :
4x - 7
Let us look at the next question on "Writing expressions"
Question 4 :
Write the given verbal phrase into mathematical expression
"One fifth of sum of 3 times a number and 9"
Answer :
( 3x + 9 ) / 5
Let us look at the next question on "Writing expressions"
Question 5 :
Write the given verbal phrase into mathematical expression
"One seventh of 3 less than 4 times a number"
Answer :
( 4x - 3 ) / 7
Let us look at the next question on "Writing expressions"
Question 6 :
Write the given verbal phrase into mathematical expression
"5 times of a number is decreased by 8"
Answer :
5x - 8
Let us look at the next question on "Writing expressions"
Question 7 :
Write the given verbal phrase into mathematical expression
"6 times of a number is increased by 15"
Answer :
6x + 15
Let us look at the next question on "Writing expressions"
Question 8 :
Write the given verbal phrase into mathematical expression
"7 less than 3 times the sum of a number and 6"
Answer :
3(x + 6) - 7
Let us look at the next question on "Writing expressions"
Question 9 :
Write the given verbal phrase into mathematical expression
"3 times the difference between a number and 8"
Answer :
3(x - 8)
Let us look at the next question on "Writing expressions"
Question 10 :
Write the given verbal phrase into mathematical expression
"One fourth of 3 times the difference between a number and 6"
Answer :
3(x - 6) / 4
Evaluating expressions - Practice questions
To have better understanding on "evaluating expressions", let us look at some practice questions.
Question 1 :
Evaluate the given expression for x = 3 and y = 5.
3x + 2y
Answer :
Plug x = 3 and y = 5 in the given expression
3(3) + 2(5) = 9 + 10 = 19
Hence, the answer is 19
Let us look at the next question on "Writing and evaluating expressions"
Question 2 :
Evaluate the given expression for m = 5 and n = 2.
m² + 2mn²
Answer :
Plug m = 5 and n = 2 in the given expression
5² + 2(5)(2)² = 25 + 40 = 65
Hence, the answer is 65
Let us look at the next question on "Writing and evaluating expressions"
Question 3 :
Evaluate the given expression for s = 5.
s² + 7s - 2
Answer :
Plug s = 5 in the given expression
5² + 7(5) - 2 = 25 + 35 - 2 = 58
Hence, the answer is 58
Let us look at the next question on "Writing and evaluating expressions"
Question 4 :
Evaluate the given expression for m = 1/3.
18m² + 3m + 7
Answer :
Plug m = 1/3 in the given expression
18(1/3)² + 3(1/3) + 7 = 2 + 1 + 7 = 10
Hence, the answer is 10
Let us look at the next question on "Writing and evaluating expressions"
Question 5 :
Evaluate the given expression for m = 13.
m² + m - 54
Answer :
Plug m = 13 in the given expression
13² + 13 -54 = 169 + 13 - 54 = 128
Hence, the answer is 128
Let us look at the next question on "Writing and evaluating expressions"
Question 6 :
Evaluate the given expression for x = 3 and y = 5.
x² + y²
Answer :
Plug x = 3 and y = 5 in the given expression
3² + 5² = 9 + 25 = 34
Hence, the answer is 34
Let us look at the next question on "Writing and evaluating expressions"
Question 7 :
Evaluate the given expression for m = 5 and n = 2.
5m² + 2m²n
Answer :
Plug m = 5 and n = 2 in the given expression
5(5)² + 2(5)²(2) = 125 + 100 = 225
Hence, the answer is 225
Let us look at the next question on "Writing and evaluating expressions"
Question 8 :
Evaluate the given expression for s = 6.
s² -3s + 10
Answer :
Plug s = 6 in the given expression
6² - 3(6) + 10 = 36 - 18 + 10 = 28
Hence, the answer is 28
Let us look at the next question on "Evaluating expressions"
Question 9 :
Evaluate the given expression for x = 2 and y = -5.
x² - 3y²
Answer :
Plug x = 2 and y = -5 in the given expression
2² + 3(-5)² = 4 + 75 = 79
Hence, the answer is 79
Let us look at the next question on "Evaluating expressions"
Question 10 :
Evaluate the given expression for m = 3.
(2m² + 5m - 7) / 2
Answer :
Plug m = 3 in the given expression
[2(3)² + 5(3) - 7] / 2 = [18 + 15 - 7 ] / 2 = 26 / 2 = 13
Hence, the answer is 13
We hope that the students would have understood the stuff given on "Writing and evaluating expressions"
Apart from the stuff given above, if you want to know more about "Writing and evaluating expressions", please click here.
If you need any other stuff, please use our google custom search here.
WORD PROBLEMS
HCF and LCM word problems
Word problems on simple equations
Word problems on linear equations
Word problems on quadratic equations
Area and perimeter word problems
Word problems on direct variation and inverse variation
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
Word problems on types of angles
Complementary and supplementary angles word problems
Markup and markdown word problems
Word problems on mixed fractrions
One step equation word problems
Linear inequalities word problems
Ratio and proportion word problems
Word problems on sets and venn diagrams
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
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 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
