my maths problem solving

hi my class room has been talking about problem solving and how to make it easy
,so like  

 When I do my maths I like to get numbers so like 1+20=21 so then i add more so I can get to a bigger number then i add the small numbers like if you don't want to do 20 +20+20+20+20=100 you can do 20 x 5= 100 
enjoy:3