Class 7 Chapter 8 Maths Comparing Quantities Notes (NCERT)

Class 7 Chapter 8 Maths Comparing Quantities Notes (NCERT) to make the chapter easier. I hope it helps you.

1. 1) Equivalent Fractions-> Ratios which have the same
value in their simple form.
2) Ratios are just the fraction form to compare numbers.
For eg->
2
3
??????� �ℎ� �??????�� ??????� 2:3.
3) Inversely proportion or a∝
1
�
is when ‘a’ ratio increases
but ‘b’ ratio decreases. The same is when ‘a’ decreases
but ‘b’ increases.
4) Direct proportion or a∝b is when the ‘a’ ratio and ‘b’
ratio increase and decrease together.
5) Percentages are Fractions with 100 in denominator.
a. Fraction in Percent->
�
�
×100=P%
b. Decimal to Percent->D×100=P%
c. Percent to Fraction->
�
100
=
�
�

d. Percent to Decimal->
�
100
=??????
e. Ratio to Percent->1:3 ??????� ���??????���=1??????+3??????=4??????
then,
1??????
4??????
×100=25%.????????????�� ��� 3??????.1:3 =
25%:75%.
6) Per cent is derived from Latin word ‘per centum’
meaning ‘per hundred’.
7) Percentage of increase and decrease-
>
??????����� �� �ℎ����
�????????????�??????��� ������
×100
8) Loss and Profit formulas->
a. Profit%=
�
??????�
×100
b. Loss%=
??????
??????�
×100
c. Profit= SP-CP
d. Loss=CP-SP

2. e. CP=SP-Profit or SP+Loss
f. SP=CP+Profit or CP-Loss
g. CP=
��×100
100−??????%
or
��×100
100+�%

h. SP=
100−??????%
100
×CP or
100+�%
100
×CP
9) Simple Interest formulas->
a. SI=
���
100

b. Amount=SI+P
c. SI=Amount-P
d. P=Amount-SI
e. P=
100×SI
�×T

f. R=
100×SI
�×T

g. T=
100×SI
�×R