Page 170 - Start Up Mathematics_6

208 18.343 km
Distance travelled on foot = km = 0.208 km
1,000 04.015 km
∴ Total distance travelled = 18.343 km + 04.015 km + 00.208 km + 00.208 km
22.566 km
= 22.566 km
Example 27: Surbhi purchased 4 kg 400 g rice, 3 kg 20 g wheat and 6 kg 850 g sugar. Find the
total weight of her purchases.
400
Solution: Quantity of rice purchased = 4 kg 400 g = 4 kg + kg = 4.400 kg
1,000
20
Quantity of wheat purchased = 3 kg 20 g = 3 kg + kg = 3.020 kg
1,000
850
Quantity of sugar purchased = 6 kg 850 g = 6 kg + 1,000 kg 4.400 kg
= 6.850 kg 3.020 kg
+ 6.850 kg
Total weight of her purchases = 4.400 kg + 3.020 kg + 6.850 kg 14.270 kg
= 14.270 kg

Subtraction of Decimals
Subtraction of 0.2 from 0.5

In the following figure, a strip is divided into 10 equal parts. Each part represents one-tenth or 0.1
of the whole figure. Also, five-tenths is shaded with a light
colour representing a positive number. Two-tenths is shaded 0.5 0.2
with a dark colour representing a negative number.
On adding a positive and a negative number, each light square gets cancelled with a dark square
and the remaining light or dark squares determine the sum, which is either positive or negative.

In the above strip, two dark squares and two light squares
cancel each other resulting in only 3 light squares as shown. 0.3
3
Thus, 3 light squares = three-tenths = 10 = 0.3
Hence, 0.5 – 0.2 = 0.3

Steps to subtract decimal numbers

We use the following steps to subtract decimal numbers:
Step 1: Convert the given decimals to like decimals.

Step 2: Write the decimal numbers one below the other keeping the decimal points directly
below each other.
Step 3: Subtract as in whole numbers.

Step 4: In the answer, place the decimal point directly below the other decimal points.

While adding or subtracting decimal numbers, we must ensure that the decimal points are one below
the other.

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