Theory:

Often we meet fractions with denominators of $$10, 100, 1000$$, etc.
For example, $$1$$ g $$=$$ $\frac{1}{1000}$kg, $$1$$ mm $$=$$ $\frac{1}{10}$ cm, $$4$$ cm $$3$$ mm $$=$$ $4\frac{3}{10}$ cm, etc.

Numbers with denominators of $$10, 100, 1000$$, etc., agreed to write down without a denominator.
First, write the integer part, and then the numerator of the fractional part. The whole number part is separated from the fractional part by a point.

For example, instead of $4\frac{3}{10}$, we write $$4.3$$ (we read: "$$4$$ integers and $$3$$ tenths").
Instead $5\frac{19}{100}$ we write $$5.19$$ (we read: "$$5$$ as a whole and $$19$$ hundredths").
Any number whose denominator of the fractional part is expressed as one with one or more zeros can be represented as a decimal fraction. If the fraction is correct, then the digit $$0$$ is written before the decimal point.
For example, instead of $\frac{21}{100}$, we write $$0.21$$ (we read: "$$0$$ integers and $$21$$ hundredths").
Important!
After the decimal point, the numerator of the fractional part should have as many digits as there are zeros in the denominator.
Therefore, for example, the number $1\frac{3}{100}$ should be written like this: $$1.03$$ (read: "$$1$$ whole and $$3$$ hundredths").