This document contains information about mathematics concepts taught in 7th grade including: 1. Circumference of a circle increases as the radius increases. 2. The number of people employed for a job is inversely proportional to the number of days taken to complete it. 3. Variation means change, and two quantities can have a direct variation where they change in the same direction or an inverse variation where they change in the opposite direction.

1. MATHEMATICS
CLASS 7TH

3. r=3cm
Radius = 6 cm
r=6cm
Radius = 3 cm
Circumference of circle
increases when we increase
the radius of circle.

5. Number of people employed is inversely
proportional to the number of days taken
to complete the job.

6. Variation comes from the word vary, it
means change.
If two quantities are related so that a
change in one causes a corresponding
change in the other, we say one varies as
the other.

7. Types of variation
1. Direct variation.
2. Inverse Variation.

8. If one quantity increases other quantity also
increases, or vice versa.

9. Increasing the number of pencils corresponding
in the increase of their cost.
Rs 5 Rs 10 Rs 15

10. Q: The total cost of 10 lottery
tickets is Rs 20. Find the cost of
25 such tickets.

11. x
(No. of
bulbs)
5 10 15 20 25 30
y
(Cost in
rupees)
20 60 100

12. If one quantity increases other quantity
decreases, or vise versa.

14. Q: If 8 men can do a job in 12
days, how long will 24 men take to
complete it?

15. No.
of
men
5 10 20 40
No.
of
days
8 2

16. Complete these phrases:
1. More jobs _______ employment.
2. More Strikes ________ production.
3. No pain _____ gain.
4. More talk ______ action.
5. The efficiency of machine ________ with
time.
6. Faster we drive, ______ time we take to
cover a distance.