Page 1 - LN-Standatd Form

SAI International School
Grade -VIII

Mathematics

CHAPTER-12: EXPONENTS AND POWERS

SUBTOPICS: STANDARD FORM, COMPARING VERY LARGE AND VERY SMALL
NUMBERS

Expanded Form:

234. 21 = 200+ 30+4+ 2/10+1/100

‘Standard Form:

There are some large numbers like 150,000,000,000 m and some very small numbers
like0.000007 m.
We have learnt how to express very large numbers in standard form in the previous
class.
For example: 150,000,000,000 = 1.5 × 10 11
0.000007 =7/ 1000000 = = 7 × 10 – 6

Comparing very large and very small numbers:
9
The diameter of the Sun is 1.4 × 10 m and the diameter of the Earth is
7
1.2756 × 10 m.
Suppose you want to compare the diameter of the Earth, with the diameter of
the Sun.
Diameter of the Sun = 1.4 × 10 m
9
Diameter of the earth = 1.2756 × 10 m
7

= .4 × = .4 × t = .4 × 2 which is approximately 100.
.2 5 × .2 5 .2 5
So, the diameter of the Sun is about 100 times the diameter of the earth.