# What's wrong with my calculator? [duplicate]

This question already has an answer here:

It is giving some very strange answers to some very simple addition. I tried adding 1 to the numbers and that was strange:

1 + 1 = 1
1 + 2 = ERROR
1 + 3 = 3
1 + 4 = 4
1 + 5 = 9
1 + 6 = 8
1 + 7 = 7
1 + 8 = 8
1 + 9 = 9


So I tried a few more, also with strange results:

2 + 4 = 8
2 + 5 = 8
3 + 4 = 9


Why is it acting so strange?

## marked as duplicate by Beastly Gerbil, Ankoganit, Mithrandir, Sid, Gareth McCaughan♦Jun 5 '17 at 16:19

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• Ah, yes. It is in fact a dupe of that. Bummer. – Forklift Jun 5 '17 at 16:17

## 2 Answers

Is it:

adding the respective components of a seven-segment display, and attempting to re-interpret the answer as a number.

• Ninja'd. I was going to post my answer, but then I saw yours is pretty much the same. And it must be throwing the error because the shape formed by 1+2 doesn't belong to any number. – Nautilus Jun 5 '17 at 16:19

I cant comment but im trying to solve this, Im thinking that number <= 4 the calculator is subtracting something, and numbers between 5 and 7 the calculator is adding something to them, numbers > 7 the calculator isnt doing annything and the calculator is ignoring the "1+" part... i hope im on the right tracks, ill try explain more when i find more sence in my toughts

i cant figure out why 1+2= error tho :/