Question

proof that 12*12=9 ???​

Answer 1

Answer:

Multiplying the two digit integers and then adding the digits of its product gives us the answer.

Multiply 12*12=144

Sum of the digits of its product 1+4+4=9

Therefore 12*12=9

In the same way

Multiply 23*23=529

Sum of the digits of its product 5+2+9=16

And now

Multiply 34*34=1156

Sum of the digits of its product 1+1+5+6=13

Therefore 34*34=13