Students learn about the other half of the numbers, to the left of zero on a number line. This is an essential foundation for later mathematics, including algebra.
Teaching students the larger numbers with three or more digits.
Students learn how the different places in a number can be changed by "skip counting" forwards or backwards in a single place.
Three-digit numbers introduce students to the "hundreds" place name, built onto the two-digit place value already learned.
Even though numbers beyond tens of thousands are not mentioned in the Australian Curriculum, learning about large numbers at this level is useful to extend students' understanding of place value and the naming conventions for large numbers. Beyond hundreds, a new pattern of sets of three related places begins, starting with thousands in hundred thousands, ten thousands and (one) thousands. This is repeated in the millions place and beyond.