194858

I started by writing the three times table. Then, I noticed that in the units column of the three times table answers, each number 1-9 only appeared once. I started at the right hand side of the calculation, and used the number in the units column of the solution to back-calculate what the figure in the units column of the number being multiplied was. Then I carried over the number in the tens column of the answer to the three times table, into the next column. Then I took that away from the number I had just solved in the code to work out what number needs to be in the units column of the next three times table answer. I did that repeatedly until the calculation was solved.