Checkers, the smartest dog in the world, was doodling in his Maths diary and come up with three equations:
A-B=C
D/E=F
G+H=I
He was about to write a fourth equation using multiplication when an interesting thought occurred to him. Instead of using a new set of numbers (J, K, L) for his fourth equation, he would use the answers of the three existing equations:
C*F=I
Now the only question in his mind was, “Can I replace the letters A through 1 with the digits 1 through 9 in such a way that all the four of my equations are correct?”
Answer
Without too much thought or fanfare, and realizing that slight variations could occur, Checkers wrote the four equations using the digits 1 through 9:
9-5=4
6/3=2
1+7=8
4*2=8