Add Up To Four Two-Digit Numbers

(B) Add up to four two-digit numbers and subtract two-digit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations

(Y2) Group, partition and rearrange collections up to 1000 in hundreds, tens and ones to facilitate more efficient counting (ACMNA028)

(Y2) Solve simple addition and subtraction problems using a range of efficient mental and written strategies (ACMNA030)

2.NBT.6 Add up to four two-digit numbers using strategies based on place value and properties of operations.