Ttc | Mathematical Brain Teasers And Logic Puzzles __hot__

I am a four-digit number. My thousands digit is twice my tens digit. My hundreds digit is three less than my units digit. The sum of all digits is 20. What number am I?

The genius of the TTC approach is the pedagogical framing. Unlike a standard puzzle book that simply gives you the answer in fine print at the back, TTC courses walk the learner through the methodology of the solution. They teach you not just how to solve a specific riddle, but how to think like a mathematician. TTC Mathematical Brain Teasers and Logic Puzzles