NA2-4: Know how many ones, tens, and hundreds are in whole numbers to at least 1000.
This means students will develop an additive view of whole number place value by knowing the significance of the position of digits in a whole number, for example, in 456 the 5 means five tens. However, many strategies for computation require a nested view of place value. This means that nested in the hundreds are tens in the same way that nested in the hundreds and tens are ones, for example, 456 has 45 tens and 456 ones. An understanding of nested place value is best demonstrated by calculations where tens must be constructed from ones, hundreds constructed from tens, tens created from breaking hundreds and ones created from breaking tens. For example, calculations like 456 + 70 = , or 456 - = 396, show whether students can apply place value in this way.