Question

Solve the following questions-
(a)The length of Ramesh’s notebook is 9 cm 5 mm. What will be its length in cm?
(b)The length of a young gram plant is 65 mm to express those lengths in cm.

Answer 1

Hint – In order to solve this problem convert millimeter in centimeter as we know one centimeter is equals to ten millimeter.
  (a)As we know, the general case,
1 meter = 100 centimeters ……(i)
And,
1 meter = 1000 millimeters ……(ii)
We can see in (i) and (ii) that both depict 1 m in centimeter and meter,
Therefore, on equating we get,

100centimeters = 1000 millimeters
1milimeter = ${\displaystyle \frac{100}{1000}}\text{centimeter = 0}\text{.1 centimeter}$
Therefore
        1milimeter = 0.1 centimeters
So,
5milimeters = 5 x 0.1 centimeters = .5 centimeters ……(iii)
So,
9 centimeters 5 millimeters = 9.5 centimeters [From (iii)]
9 cm 5mm = 9.5 cm
So the length of Ramesh’s book is 9.5 cm .
   (b)As we know,
1 meter = 100 centimeters ……(i)
And,
1 meter = 1000 millimeters ……(ii)
We can see in (i) and (ii) that both depict 1 m in centimeter and meter,
Therefore, on equating we get,

100 centimeters = 1000 millimeters
1 millimeter = ${\displaystyle \frac{100}{1000}}\text{centimeter = 0}\text{.1 centimeter}$
Therefore,
         1 millimeter = 0.1 centimeters
So,
65 millimeters = 65 x 0.1 centimeters = 6.5 centimeters ……(iii)
So,
65 milimeters = 6.5 centimeters [From (iii)]
65 mm = 6.5 cm
So, the length of the gram plant is 6.5 cm.

Note – In these types of questions we have to know the concept of units and measurement and we should know how to convert one unit into another, basically, we should know conversion. Here we have changed mm in cm, as we know that value of 1m in mm and cm so we can get the relation between cm and mm as I have done above. If you can remember the direct conversion then you can do it but if you didn’t remember it then calculate it with the help of generally used SI units.