Mathematics | Class: JSS1 | Term: 1st

Expressing One Quantity as a Percentage of Another

len Alfred Ajibola - 01st February, 2026 @ 09:17 PM

Topics in Mathematics

Linear Equation in Mathematics Word Problems leading to Algebraic Expression BODMAS in Algebra Multiplication and Division in Algebra Addition and Subtraction in Algebra Multiplication of Number Bases Subtraction of Number Bases Addition of Number Bases Division of Number Base Number Base Conversion Number Base System Significant Figures Rounding Off Numbers Decimal Place Value Fraction Word Problems Word Problems in Fraction Multiplication and Division of Fractions Addition and Subtraction of Fractions Expressing One Quantity as a Percentage of Another Expressing One Quantity as a Fraction of Another


Academic Questions in Mathematics

Please click here to see all Questions and Answers

Decagon - Len Academy

What type of polygon is shown in the above image?

  • A. Nonagon

  • B. Decagon

  • C. Octagon

  • D. Hexagon

  • E. Hepagon

  • F. Pentagon

Which of the following is not part of a circle?

  • A. Section

  • B. Sector

  • C. Segment

  • D. Semicircle

  • E. Secant

  • F. Center

Acute Angle - Len Academy

What angle is shown in the above image?

  • A. Complementary

  • B. Supplementary

  • C. Acute

  • D. Obtuse

  • E. Reflex

  • F. Straight

An angle greater than 90o but less than 180o is termed _____.

  • A. Complementary

  • B. Supplementary

  • C. Acute

  • D. Obtuse

  • E. Reflex

  • F. Straight

Factorize 12a2 - 20a + 3

  • A. (6a - 1)(2a - 3)

  • B. (6a - 1)(2a + 3)

  • C. (6a + 1)(2a - 3)

  • D. (6a + 1)(2a + 3)

  • E. (-6a + 1)(2a - 3)

  • F. (-6a + 1)(2a + 3)

Simplify 10ab + 7ab

  • A. 17ab2

  • B. 17a2b2

  • C. 3ab2

  • D. 3a2b2

  • E. 17ab

  • F 3ab

Which of the following is not a type of angle?

  • A. Right angle

  • B. Left Angle

  • C. Acute Angle

  • D. Complete Angle

  • E. Straight Angle

  • F. Reflex angle

Two lines that can never meet each other are best considered as _____ lines.

  • A. straight
  • B. vertical
  • C. horizontal
  • D. parallel
  • E. oblique
  • F. perpendicular



Expressing Quantities and Percentages 


Expressing one quantity as a percentage of another simply means to make a correct fraction of a given value in a question, then multiple the fraction by 100.

When solving the question of expressing one quantity as a percentage of another, always make sure that both quantities are of the same unit.

To correctly express one quantity as a percentage of another, place the first quantity as the top number (numerator) and the second quantity (the whole) as the bottom number (denominator), and then simplify the fraction if need be. The next important step is to multiply your resultant fraction by 100.

Please read on expressing one quantity as a fraction of another here.

You can read on the addition of number bases here.

 


Worked Examples on Expressing One Quantity as a Percentage of Another


Example 1
  • In a box of 200 oranges, 18 are bad. What percentage is bad? What percentage is good?

Solution 

Number of oranges in the box = 200

Number of bad oranges = 18

Number of good oranges = 200 - 18 = 182

Percentage of bad oranges 

18/200 × 100

1800/200

  • 9%

Percentage of good oranges

182/200 × 100

18200/200

  • 91%

 

Example 2
  • A worker hammers a post of 2.2m long into the ground, and 66cm of the post went below the ground. What percentage of the post remains below and above the ground?

Solution 

Convert to same unit. Let's convert centimeter to meter in this instance.

100cm -> 1m

66cm -> y meter

Cross multiply 

y meter × 100cm = 66cm × 1m

Make y the subject of the formula

y meter = 66/100

y meter = 0.66m

Therefore, 0.66m of post entered the ground while (2.2m - 0.66m) remained above the ground.

Percentage of post below the ground

0.66/2.2 × 100

66/2.2

  • 30%

Percentage of post above the ground

2.2m - 0.66m = 1.54m

1.54/2.2 × 100

154/2.2

  • 70%

 

Example 3
  • Bisola sold 7/8 of her oranges during the market day. What percentage was this? If she has 16 dozens of oranges left in her basket. How many did she sell?

Solution 

Percentage of oranges sold by Bisola 

7/8 × 100 = 700/8

  • 87.5%

Fraction of oranges not sold by Bisola is the total oranges (1) minus the fraction sold:

1 - 7/8 = 1/8

Recall that 1 dozen = 12

If she has 16 dozens of oranges left in the basket, therefore, 16 dozens  -> 16 × 12 = 192

The number 192 represents the fraction (1/8) of oranges that was not sold.

Therefore, 1/8 of Total Oranges = Oranges that are not sold

1/8 x Total Oranges = 192

Total Oranges = 192 × 8 = 1536

Number of oranges sold by Bisola = Total Oranges minus Oranges not sold

1536 - 192 = 1344

  • 1344 Oranges were sold by Bisola

OR

The number sold = 7/8 of the Total Oranges

7/8 × 1536 = 10752/8

  • 1344

 

Example 4
  • A man spent 1/3 of his salary on food and 1/4 on school fees of his children. What percentage of his salary is left?

Solution 

Since his expenses are in fractions, therefore his salary is a whole number '1'.

Money remaining after spending on salary

1 - 1/3 = 2/3

Money remaining after paying school fees

2/3 - 1/4 = 5/12

Remainder of his salary in percentage 

5/12 x 100 = 500/12

  • 41 2/3% or 41.67%

Please read on work problems in fractions here.

Please read on word problems leading to algebraic expressions here.

 


Assignment on Expressing a Quantity as a Percentage of another


Question 1

Express the following as a percentage of the second.

  • 10 Naira, 1000 Naira

  • 50 Cent, 2 Dollars

  • 300 Gram, 2 Kilogram

  • 800 Milliliters, 1.5 Liters

  • 30 Millimeters, 3 Centimeters 

 

Question 2

26cm of a wool is cut off a board of 130cm long. What percentage has been cut off?

 

Question 3

A piece of elastic is 1m long. If it is stretched to a length of 600cm. What percentage of the original length is the increase?

Please read on linear equation here.

Please read on mathematics week 5 topic for jss1 first term here.

Please read on mathematics scheme of work for jss1 first term here.

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Amazing facts in Mathematics

The opposite sides of a dice will always give a sum of seven

31,556,926 seconds makes one year

From 0 through 1000, the only number that has the letter 'a' in it is 'one thousand'

÷

The division symbol '÷' is actually called an obelus

Four is the only number in the English language that is spelt with the same number of letters as the number (4) itself

40 is spelt as forty and not 'fourty'. It is the only number that is spelt with letters arranged in alphabetical order

An odd number is a number that cannot be divisible by 2.

Every odd number has an 'e' in its spelling. They include:

  • One
  • Three
  • Five
  • Seven
  • Nine

555 in Thailand sounds like 'hahaha'. This is because the number '5' means 'ha' in Thailand

In mathematics, 10! means 10 factorial. Below is its calculation:

10! = 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 3628800

Interestingly, 3628800 seconds is the same as 42 days

42 days is the same as 6 weeks

We can therefore say that 10! equals 6 weeks or 3628800 seconds in mathematics

When you multiply 111,111,111 by 111,111,111; the result equals 12,345,678,987,654,321


Notable points in Mathematics

Let's use algebra to explain the simple statement below:

I am a number. When you subtract 3 from me, the result is 9. what number am I ?

Of course we know the answer is 12. You probably guessed it from your mind because it was that simple. The truth is, We could have a much more complicated statement of such; and that is where algebra comes into play.

Now, to apply algebra in the above statement, we use letters or alphabets to represent the unknown number(s). So using algebra, we can write:

  • Let the number be y

  • y - 3 = 9

  • y = 9 + 3

  • y = 12

Please read more on algebra here

Sides of a right angle triangle - Len Academy

 

The image above shows a right angled triangle. The angle of the above right triangle is denoted as θ. Below are some points to note:

Hypotenuse is always the longest side of the triangle.

Opposite is the side opposite the angle (θ)

Adjacent is the shorter side next to the angle (θ)

Each of Sin θ, cos θ and tan θ are the ratio of sides of the right triangle. They are calculated by using the formula (margic word) sohcahtoa:

Sohcahtoa - Len Academy

soh

Sin θ = Opposite/Hypotenuse

cah

Cos θ = Adjacent/Hypotenuse

toa

Tan θ = Opposite/Adjacent

Please read more on sine, cosine and tangent here

Circumference of a Circle - Len Academy

Circumference in mathematics means the distance around the edge of a circle (or a another curved surface).

Circumference is to circle or any other curved surface

Perimeter of a Rectangle - Len Academy

Perimeter means the distance around a square or rectangle or polygon.

Perimeter is to square or rectangle or polygon