I mean, is the question 20 - 27 =? Or it's something else? Lol.
20 - 27 = -7, it's very straightforward cannot write it in more detailed way. When we substract a number from another and the first one is smaller the result is a negative number. Imagine someone sells up to 3 apples, you ask him to give you 5. He gives you all 3 of his so he has 0 but you force him to go and get another 2 for you. He lost another 2, so he has less than 0 now. He has -2 apples: 3 - 5 = -2.
Now, I don't know if this is the question or these are set of exercises you must solve and your picture just didn't upload. Let me know if you need help with anything else.
