Question

Multiply $3.5\times 0.9$

Answer 1

Multiplying decimal numbers-

Ignore the decimal point and multiply

so, $35\times 9=315\left[\because 09=9\right]$

Count the number of digits after the decimal point in both the numbers, we have $1$digit after decimal in $3.5$ and $1$digit in $0.9$

So, place the decimal after two digits from the right in the product. $\left[\because 1+1=2\right]$

$\Rightarrow 3.5\times 0.9=3.15$

Hence , product of $3.5\times 0.9$ is $3.15$