5 7/12 + 4 6/12 = 9 13/12 = 1 1/12 what's the error analysis?

5 7/12 + 4 6/12 = 9 13/12 is correct but 9 13/12 is equal to 10 1/12 not 1 1/12  because 13/12 is 1 1/12 and you have to add 1 1/12 to 9. So the error analysis is simplifying  9 13/12 to 1 1/12.

i am sure it will be 90 degrees.

step-by-step explanation:

2nd one in the first row is correct