A cryptarithm is a math puzzle in which the digits in a simple equation are replaced with letters. Each digit is represented by only one letter, and each letter represents a different digit. So, for example, we might represent 51+50 = 101 as AB + AC = BCB. In the cryptarithm SEND + MORE = MONEY, what digit does the letter Y represent?

Step-by-step explanation:

Hello, let's do it step by step and see what we can find.

We assume that M is different from 0, otherwise we could find several different solutions I would think.

It means that S + M is greater than 10, otherwise the number of digit of the result would have been 4 and not 5.

The only possible number for M is then 1. M = 1

But then, S can only by 9, otherwise S + 1 < 10. S = 9

S + 1 = 10 + O if there is no carry over, so S = 9 + O

1 + S + 1 = 10 + O if there is a carry, so S = 8 + O

So O = 0 or O = 1. Wait !? M is already equal to 1 so O must be 0

E cannot be equal to N so 1 + E = N, meaning that there must be a carry over from column second from the right.

and E < 9 as we know that there is no carry over from column 3 from the right.

N + R = 10 + E => 1 + E + R = 10 + E => R = 9, impossible, as S=9

or 1 + N + R = 10 + E => 1 + 1 + E + R = 10 + E => R = 8

And there is a carry over from the column 1 from the right, so:

Y cannot be 0 or 1, as already used so D + E > 11

8 and 9 are already taken so we could have 7 + 5 = 12, 7 + 6 = 13 and that's it.

It means that E is 7 or D is 7.

If E is 7 then E+1=9=N, impossible, so D = 7

Then, E is 5 or 6

if E = 6 E + 1 = N = 7, impossible, so E = 5 and N = 6.

And 7 + 5 = 12 so Y = 2.

Hope this helps.

Do not hesitate if you need further explanation.

Thank you

-2

7 - 9 = -2

reversed:

-2 + 9 = 7