Question

Ravi and Raju measured the length of their pencils, Ravi's pencil was $7cm$ and $5mm$ long and Raju's pencil was $8cm$ and $3mm$ long. Write the length of Ravi's and Raju's pencil in $cm$ using decimal.

Answer 1

$1cm=10mm$.

Here, we will convert the given length in $mm$ (millimeters) first and then into $cm$(centimeters).

Ravi's pencil was $7cm$ and $5mm$ long.

For converting $cm$ into $mm$ we have to multiply the value by $10$

So, $7cm5mm=7\times 10+5$

$=70+5$

$=75mm$.

Now, for converting $mm$ into $cm$ we will divide the value obtained by $10$.

So, $75mm=\frac{75}{10}cm$

$=7.5cm$ (As many number of zero in the denominator that many numbers we will count from the right side and place the decimal point)

Raju's pencil was $8cm$ and $3mm$ long,

, $8cm3mm=8\times 10+3$

$=80+3$

$=83mm$.

$83mm=\frac{83}{10}cm$

$=8.3cm$.

Therefore, the length of Ravi's pencil is $7.5cm$ and the length of Raju's pencil is $8.3cm$.