Addition and Subtraction of Measuring Length

We will discuss about addition and subtraction of measuring length. We know the measure of length is required to know how tall a boy or a girl is or, how long the cloth is.

Meter is the standard unit of length. If we divide the length of a meter in 100 equal parts, each part is known as a centimeter. Centimeter is also a unit to measure small lengths.

Students use a scale to measure different lengths. Scale (ruler), measuring tape, cloth measuring rod, etc., are made to measure in meters and centimeters. Meters and centimeters are written as ‘m’ and ‘cm’ in brief as 5 m, 8 m, 2.5 cm, 7.5 cm etc.

Relationship between meter and centimeter:

We know one of the 100 parts of a meter is called a centimeter.

So, 1 meter = 100 centimeters

or, 1 m = 100 cm

and, 100 cm = 1 m

Addition and subtraction of measuring length in meter and centimeter:

1. A room is of 6 m length and 4 m breadth.

(i) Find the sum of its length and breadth.

(ii) Find the difference in length and breadth.

Solution:

(i) Sum = 6 m + 4 m = 10 m

or,                6 m

                +  4 m

                   10 m

Therefore, sum = 10 m

(ii) Difference = 6 m – 4 m = 2 m

or,                 6 m

                 -  4 m

                    2 m

Therefore, difference = 2 m

2. There are two line-segments. One is 8 cm long and other is 5 cm long.

(i) Find the total length of both the line-segments.

(ii) Find the difference between the lengths of the segments.

Solution:

(i) Total length = 8 cm + 5 cm = 13 cm

or,                 8 cm

                +  5 cm

                  13 cm

Therefore, total length of both the line-segments = 13 cm

(ii) Difference = 8 cm - 5 cm = 3 cm

or,                8 cm

                -  5 cm

                   3 cm

Therefore, difference between the lengths of the segments = 3 cm

3rd Grade Math Worksheets

3rd Grade Math Lessons

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