Decimals

2.3 Decimals

2.2

Decimals

MULTIPLICATION OF DECIMALS

The diagram below shows the position of R, S, and T. The ST distance is 0.3 times the RS distance. What is the distance, in km, from S to T?

MATHEMATICAL SENTENCE:
\(0.3\space\text{km}\times0.4\space\text{km}=\)
\(\begin{array} {rr} \small{\color{red}{1}}\quad\;\; \\0\;.\;3 \\\times\quad0\;.\;4 \\\hline\quad1\;\;\;\,2 \\+\quad0\;\;\;\,0\;\;\;\,0 \\\hline 0\;\,.\,1\;\;\;2 \\\hline \end{array}\)

Tips: The position of the decimal point of the product depends on the total number of decimal places in the number being multiplied.
\(0.3\text{ km}\times0.4\text{ km}=0.12\text{ km}\)

So, the distance from S to T is 0.12 km.

DIVISION OF DECIMALS

Ahmad will pour \(2.5\ l\) the same amount of orange juice into several bottles. Each bottle contains \(0.5\ l\). How many bottles are needed?

MATHEMATICAL SENTENCE:

\(2.5\ l\div0.5\ l=\)

\(\;\;\;\;\;\;\;\,\;\;5\,\\0.5\overline{\smash{)}\;2.5}\;\\\,\underline{-\;\;\;2.5}\;\;\, \\\;\;\;\;\;\;\;\;\;0\)

So, the number of bottles needed is 5 bottles.

Quick Notes