You can go to an overview of all the curricula here.
Number and place value
ACMNA099 – Use estimation and rounding to check the reasonableness of answers to calculations
Samples: Two digit addition (estimating). Division (estimation) - 1. Rounding numbers to the nearest 10.
6.NA.1 – Apply additive and simple multiplicative strategies flexibly to:
6.NA.1.a – Combine or partition whole numbers, including performing mixed operations and using addition and subtraction as inverse operations
Samples: Write numbers – to 100,000. Reading numbers – to 100,000. Comparing numbers – to 100,000.