This is a great tool for practicing the calculation tips used in a mental maths series. Below is the link to the video. Func 1: Up to 3-digit number * 11. Func 2: Up to 2-digit number ending in 5 squared. Func 3: Up to 2-digit number * 1st digit of previous number and 2nd digit of 10 - 2nd digit of previous number.
https://www.youtube.com/watch?v=1wAr2Kbe-GM
