Tenths

Cut one whole into 10 equal pieces. Each piece is one tenth, or 1/10.

A shorter way to write it

7/10 can be written 0.7. It is the same amount, written differently.

The dot has a name.

Decimal point separates the whole ones from the pieces smaller than one.

Say it as a fraction

0.7 is read "seven tenths", exactly as 7/10 is.

The place value pattern simply continues

Going right, each place is a tenth of the one before: hundreds, tens, ones, then tenths. The decimal point is only a marker showing where the ones place ends. Nothing new was invented — the rule from lesson one of this year kept going.

Two ways to write the same number

0.7 and 7/10 are the same number in the same place on the number line. Decimals are fractions with denominators of ten, a hundred, a thousand, written in a compact form that fits the place value columns.

Reading them aloud

0.7 is "seven tenths". Saying it that way keeps the connection to fractions alive. Saying "zero point seven" is fine in conversation but tells you nothing about the size, which is why the fractional reading is preferred while learning.

Tenths on the number line

Split the space between 0 and 1 into ten equal parts and each mark is a tenth. 0.7 sits seven of them along. This is the same picture as the fraction number line, which is the point — decimals are not a new kind of number.