Topic Details (Notes format)

How to Calculate the Percentage of a Number?

Subject: Mathematics

Book: Maths Mastery

Percentages are central to countless real-world applications—from calculating exam marks to determining discounts and interest rates. The general formula to find a percentage is: (Part / Whole) × 100%. However, if you already know the rate and the whole, use Percentage of a Number = (Rate ÷ 100) × Whole. For example, to calculate 20% of 150, convert 20% to 0.20, then multiply: 0.20 × 150 = 30. This concept is pivotal in areas like finance and data analysis, so practice by computing percentages for tips in restaurants, taxes on shopping bills, or proportionate contributions in group projects. Mastering this skill builds a strong foundation for advanced percentage operations such as percentage increase, decrease, and compound interest calculations.

Practice Questions

What is the HCF of 72 and 120?

View Question

If sin(A) = 1/2 and A is acute, what is the value of A?

View Question

What is the LCM of 15 and 20?

View Question

The perimeter of a rectangle is 40 cm, and its length is 12 cm. What is its width?

View Question

If a cylinder has a radius of 7 cm and height of 10 cm, what is its volume?

View Question

If log(100) = 2 and log(10) = 1, what is log(1000)?

View Question

If a:b = 7:9 and b:c = 5:6, what is a:c?

View Question

What is the sum of all even numbers between 1 and 50?

View Question

A rectangle has a length of 10 cm and a width of 5 cm. What is the diagonal of the rectangle?

View Question

If the radius of a circle is doubled, what happens to its area?

View Question