There's a forest behind a town. To improve the air quality, the people of the town started a tree planting initiative and planted $65$ trees everyday. How many trees will they have planted after $3$ weeks?

The correct option is C $1365$
Trees planted in $1$ day $=65$ trees
We need to find the number of trees planted after $3$ weeks.

How many days are there in $3$ weeks?
$1$ week $=7$ days
$3$ weeks $=7\times 3$ days
$=21$ days

Trees planted after $3$ weeks (i.e. $21$ days) $=65\times 21$ trees

The product $21\times 65$ can be evaluated as:

First, we would multiply the units digit of $21$, i.e., $1$ with $65$.


Now, we would multiply the tens digit of $21$, i.e., $2$ with $65$.

Finally, we would add $65$ and $1300$ to get the answer.


$21\times 65$ trees $=1365$ trees
Number of trees planted in $3$ weeks $=1365$ trees