# Glossary

Decimals with different numbers of digits after the decimal points.

Selects a named numeral from a randomly displayed group of displayed numerals.

Expresses a number in equivalent ways by interpreting the relationship between the place value powers of ten. For example, 243 can be renamed 2 hundreds and 43 ones or 24 tens and 3 ones.

Adding the same number again and again. A strategy sometimes used for multiplication.

The volume of a rectangular prism (length x width x height) can be established by first finding the number of cubes covering the base and then building up in repeated layers.

One revolution is a complete turn of 360°.

Rhythmic counting uses the rhythm of the number words (e.g. five, ten, fifteen, twenty, twenty-five, thirty, …).

Produces the correct sequence of number words from memory but without reference to their meaning.

Technically, rote counting in English is usually limited to 20, as students typically make use of the patterns in the number words beyond 20.

The decimal expansion of a real number is rounded when it is approximated by a terminating decimal that has a given number of decimal digits to the right of the decimal point.

Rounding to  decimal places is achieved by removing all decimal digits beyond (to the right of) the digit to the right of the decimal place, and adjusting the remaining digits where necessary.

If the first digit removed (the  digit) is less than 5 the preceding digit is not changed.

For example, 4.02749 becomes 4.027 when rounded to 3 decimal places.

If the first digit removed is greater than 5, or 5 and some succeeding digit is non-zero, the preceding digit is increased by 1. For example, 6.1234586 becomes  6.12346 when rounded to 5 decimal places.