A B C D question

[sour marsh]

I gone mad about this. Does anyone has a clue how to solve these type of questions quickly? Or do I have to keep trying each number like a robot.

A, B, C and D numbers are different from each others
Find D

[alpine drift]

A=2
B=3
C=1
D=7
2317+231+23+2=

you can do it by rough inspection

start by assuming A is 2, A is either 2 or 1, so pick one to start with

then gradually work across, if you find 2 of them to be the same then move along 1 and try and get it to add up to roll over (like having 23 in the ones spot)

[sour marsh]

I didn't understand. I get that the values you gave does work but until C, Instantly my mind goes to say that it must be 2 if 2+3+C = 7. Then the D cannot be found. How did you guess that C must be 1

because 2 + 3 + 1 is not 7

[alpine drift]

it's what I said about getting it to roll over

because if you get the ones place to sum to 13 then you get +1 to the 10s

[sour marsh]

so above 2 would be too unnecessary

thats why we gone to 1 instead

and c cannot be 2 3