1x3=3
4x3=3 like 12 ->1+2=3
7x3=21=3 like 2+1
10x=30=3
11x3=33=(1+1)x3x3=33
but (1+1)x3=6=>3+3
12x3=36=(1+2)x3=9=3+6=9
24x3=6x3=18=2+4+3=72=9
96x3=9+6+3=18=9=>96x3=288=9

Did you understand the method and what it teaches?

Example:
127x3=13=4=126+1=(42+1)x3+1=7=6+1=9+1=381=12=3 cause 1+2+7=10+3=4=4x3=12=3

Can you understand?
If add all numbers, 9, is 3x3
+1=3
+2=6