Tina had $$20\ m\ 5\ cm$$ long cloth. She cuts $$4\ m\ 50\ cm$$ length of cloth from this for making a curtain. How much cloth is left with her?
Length of cloth Tina had
$$=20\ m\ 5\ cm= 20\ m\ +\ 0.05\ m$$ $$\left[\because \dfrac {1}{100}cm = 0.01\ m\right]$$
$$=(20 + 0.05)\ m = 20.05\ m$$
Length of cloth cut of $$4\ m\ 50\ cm$$
$$=4\ m + 50\ cm$$
$$=4\ m + \dfrac {50}{100}m =4\ m + 0.50\ m$$ $$\left[\because \dfrac {1}{100}cm = 0.01\ m\right]$$
$$=(4 + 0.50)\ m= 4.50\ m$$
$$\therefore$$ Length of cloth left $$= 20.05\ m - 4.50\ m$$
$$=15.55$$
$$\begin{matrix}
& 1 & 9 & & 10 & & \\ & 2 & 0 &
\cdot & 0 & 5 & m \\ - & & 4 & \cdot & 5
& 0 & m \\ = & 1 & 5 & \cdot & 5 & 5 &
m \end{matrix}$$