3 can be represented as (tri)

Which is used in many situations

TRIangle, Potassium TRIchloride

TRIcycle…

If you want to find out if 3 can divide a number just add up the digits of the number and see if 3 can divide it

e.g. 273

   2+7+3=12

Therefore 3 can divide 273.

   273÷3=91