To calculate 9*52, we note that 9=10-1, so mentally calculate 9(52) =(10-1)(52) =520-52 [ subtract 20 from each number] =(520-20)-(52-20) =500-32 =468.
Alternatively, 9*52=9*50+9*2=450+18=468
If you're good with multiplication and division, 9*52=3*3(52)=3*156=450+18=468
