@eye-of-horus-42 said6/10/6
Draw a square 30x30mm,on each corners write number 6 outside of the square,in side the square write number 20, on top and bottom of number 20 outside of the square write number 10. All the numbers added equal 64,remove two numbers,so the rest of the numbers added,equals to number 40 GOOD LUCK..
_/20/_
6/10/6
Based on the solution given by the poster, the square shape does not matter at all. Remove one of the 6s and the 0 from the 20 to make it 2 removes 24 from 64 giving 40