Decimal numbers are numbers that include a decimal point to show parts of a whole. The digits to the right of the decimal point represent values that are less than one whole unit.
The decimal point separates the whole-number part from the fractional part. Everything to the left of the point is a whole number, and everything to the right represents parts of one whole.
Each digit in a decimal number has a specific place value based on its position. Moving right from the decimal point, the first place is tenths, the second is hundredths, and the third is thousandths.
Remember: Each place value to the right of the decimal point is ten times smaller than the one before it.
Place value models, such as grids or base-ten blocks, help show how many wholes, tenths, hundredths, or thousandths a decimal has.
When reading a place value model, count the shaded parts carefully. Always identify which part of the model represents tenths or hundredths before writing the decimal number.
When writing a decimal, use a decimal point to separate the whole number from the fractional part. Say the decimal aloud the same way you would read it in words, then write it using numbers and a decimal point.
Do not say “point” when reading a decimal in words. Instead, say “and” to separate the whole number from the fractional part, such as “three and six tenths” for 3.6.
We can compare decimal numbers by looking at their place values or by using place value models. The number with more shaded parts or a greater value in the first different place is larger.
Always compare decimals from left to right: ones, tenths, hundredths, and so on. Add zeros if needed to make them easier to compare (for example, compare 2.40 and 2.35).