Replacing numbers with letters is called cryptography, and a cryptogram is a math problem, in which letters stand for numbers. For example:
The problem is, to find the number ABC, which has been multiplied by itself.
Let's start with C., the last digit of the number searched for and the square. There are only three numbers, the square of which she herself has as the last digit. There are:
0 (0 · 0 = 0), 5 (5 · 5 = 25) and 6 (6 · 6 = 36).
C cannot = 0 being, because if we have any number 0 multiply, we receive 0, but here B multiplied by C results in E..
C can't either 6 being. Because in the middle row of addition we have D + C + C = D. Is C = 6, so it is not possible, that D + 6 + 6 = D is, because D + 12 cannot give D again.
So C must 5 being.
But we also know the number, which the letter A represents; because we see in the multiplication, that A · ABC = ABC; so A can only 1 mean. So we now have two digits, namely A = 1 and C = 5. We now write down the task again and replace the known letters with the digits, that they represent:
We now consider the middle row D again + 5 + 5 = D. The 10 so we can stand out from this series and wear one for it 1 in the preceding vertical row. Now we see, that 1 + B + B = 5 is; but the only number, which can stand for B., is therefore 2, gives 1 + 2 + 2 = 5 is.
The task is now solved: ABC = 125. We want to try, still to solve a cryptogram: The opposite is the answer.
