**Challenge:** Build a JavaScript Calculator test 8 and 12 error

Tell us what’s happening:
Describe your issue in detail here.

it fails on test 8 and 12 but couldn’t get what this tests are about. calculator works fine

(test 12) when i entered 10.5-5.5 it shows 5 but tests say that my calculator showed -5

Your code so far
my solution

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User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Challenge: Build a JavaScript Calculator

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