Page 173 - Start Up Mathematics_6

At a Glance

1. Every fraction with denominator 10, 100, 1,000, etc. is known as a decimal fraction.
2. If one block or strip representing one unit is divided into 10 equal parts, then each part
1
represents one-tenth, i.e., or 0.1 of a unit. Similarly, if one strip or block is divided into
10
100 equal parts, then each part represents one-hundredth, i.e., 1 or 0.01 of a unit.
100

3. In the place value table, as we go from the left to the right, the multiplying factor becomes
1

10 of the previous factor.
4. The decimals having same number of decimal places are called like decimals, else they are
called unlike decimals.

5. Comparison of decimals: We can compare decimal numbers by first changing them into
like decimals and then comparing their whole parts. If the whole parts are equal, then we
compare the decimal parts.

6. Addition and subtraction of decimals: To add or subtract decimal numbers, first change
them into like decimals, then arrange them vertically according to the place value of the
digits. Then add or subtract as required.

Review Exercises

Multiple ChoiCe Questions
1. The place value of 9 in 8.2091 is:

9 1 9
(a) 0.209 (b) (c) (d)
100 1,000 1,000
2. Which amongst the following decimals has the greatest value?

(a) 3.42 (b) 3.24 (c) 3.042 (d) 3.3999

3. 3 kg 40 g is equal to:
(a) 3.040 kg (b) 3.004 kg (c) 3.4 kg (d) 340 g

4. 100 metres is equal to:
(a) 1 km (b) 0.1 km (c) 0.01 km (d) 0.001 km

4 7
5. The value of expression 3 + + is:
10 100

(a) 34.07 (b) 0.347 (c) 3.47 (d) 347
6. 7 L 680 mL is:

(a) 7.68 L (b) 7.068 L (c) 76.8 L (d) 76.08 L
7. A decimal number lying between 3.2 and 3.22 is:

(a) 3.118 (b) 3.218 (c) 3.3 (d) 3.23

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