Page 28 - Concepts of Reasoning-8

CHAPTER

Worksheet-2.1 exponents 2

Expressing Very Small Numbers Using Exponents, Scientific Notation

1. The following decimal numbers are expressed in exponential form. Circle the error in the
expansion and correct it. One is done for your reference.

S. No Decimal Exponential form
–2
1
1
2
234.567 2×10 +3×10 ×4+10°+5×10 +6×10 +7×10 –3
–1
2
1
–2
Correct expansion 2×10 +3×10 +4×10°+5×10 +6×10 +7×10 –3
1
2
–1
a. 678.901 6×10 +7×10 +8×10°+9×10 +1×10 –3
Correct expansion
1
–2
3
2
b. 3456.0021 3×10 +4×10 +5×10 +6×10°+2×10 +1×10 –4
Correct expansion
2
–1
1
c. 432.01 4×10 +3×10 +2×10 +1×10 –2
Correct expansion
1
2
4
3
–1
d. 12556.12 1×10 +2×10 +5×10 +5×10 +6×10°+1×10 +2×10 –3
Correct expansion
1
3
e. 1023.01 1×10 +2×10 +3×10°+1×10 –2
Correct expansion
2. Match the following :
a. 0.0000000032 ( ) i. 32 × 10 –5
b. 0.0000032 ( ) ii. 32 × 10 –6
c. 0.000032 ( ) iii. 32 × 10 –9
d. 0.032 ( ) iv. 32 × 10 –6

e. 0.00032 ( ) v. 32 × 10 –3

3. State True (T) or False (F).

–32
32
a. Multiplicative inverse of –145 is 145
b. 0.042 = 42 × 10 –3

0.000125 –3
c. = 25 × 10
0.005
d. 0.00666 = 66.6 × 10 –5

–2
e. 50 × 10 = 0.5

28 Reasoning - 8