Convert $49$ into a binary number.

Given number is $49$.

To convert a decimal number to binary, we divide it successively by $2$ & use the quotient obtained in this step as the dividend for the next step. Continue this process until the quotient becomes $0$.

$49÷2=24$, remainder is $1$

$24÷2=12$, remainder is $0$

$12÷2=6$, remainder is $0$

$6÷2=3$, remainder is $0$

$3÷2=1$, remainder is $1$

$1÷2=0$, remainder is $1$

Now read from the bottom to top as $110001$.

Hence, ${49}_{10}={110001}_2$