### Mathematics Class VII

Integers
Fractions and Decimals
Exponents and Powers
Algebraic Equations
Simple Linear Equations
Lines and Angles
Comparing Quantities
Congruence of Triangles
Rational Numbers
Perimeter and Area
Data Handling
Practical Geometry
Symmetry
Visualising Solid Shapes

# Fun with estimation

With the help of percentage, we can estimate the parts of an area.

Example

What percent of the given figure is shaded?

Solution

First, we have to find the fraction of the shaded portion.

##### Use of Percentages
• Interpreting percentages

To use the percentages in real life we must be able to interpret the percentage.

Example

If we say that Seema is spending 20% of her income then it means that Seema is spending Rs. 25 out of every Rs. 100 she earns.

• Converting percentages to “How many”.

Example

If 20% of students get a distinction out of 45 students in a class, then how many students got the distinction?

Solution

The number of students got distinction = [20/100] × 45 = 9.

Hence, 9 students out of 45 got the distinction.

• Increase or decrease as Percent
• Sometimes we have to find the increase or decrease in certain quantities as a percentage. Like the increase in population, decrease in sale etc.

Example

The total marks of Charlie increased from 365 to 380 from last year’s result. Find the increase in percentage.

Solution

Original amount = Marks of Charlie last year = 365

Amount of change = increase in the number of marks = 380 – 365 = 15.

Therefore,

Scroll to Top