A half way step to understanding the standard written method of multiplication.
Not as hard as it sounds. Multiply the number by 50 and then subtract the number.
Yet another quick tip for helping with mental arithmetic. Multiply a 2-digit number by 101. Multiply by 100 and then add the number.
Quick tip on how to multiply by 99 'in your head'. Endless practice to help consolidate skills.
Multiply the units and put in the answer. Multiply the tenths and put in the answer. Add the 2 answers together.
The easiest way to do most of these is to multiply by 10 and then adjust if necessary. Not long to get as many as possible!