2 1/4+3 3/4=6?

4 5/6-3 1/6=1 2/3

8 5/12- 1 1/2= 7 1/3

They are right -- assuming there's a typo in the third problem.

9 3/4-7 1/2= 2 1/4

2 1/8+5 7/8=8

1 2/3+4 8/9=6 5/9

All are correct. :-)

To solve these addition and subtraction problems involving mixed numbers, you need to follow these steps:

1. Convert the mixed numbers into improper fractions (if necessary).

For example, in the first problem, 2 1/4 becomes (2*(4) + 1) / 4 = 9/4, and 3 3/4 becomes (3*(4) + 3) / 4 = 15/4.

2. Perform the addition or subtraction operation for the fractions.

- In the first problem, 9/4 + 15/4 = (9 + 15) / 4 = 24/4 = 6. So, 2 1/4 + 3 3/4 = 6.

3. Simplify the resulting fraction, if necessary.

Now, let's move on to the second problem.

For the second problem, 4 5/6 is already an improper fraction. Similarly, 3 1/6 becomes (3*(6) + 1) / 6 = 19/6.

Performing subtraction, 4 5/6 - 3 1/6 = (29/6) - (19/6) = 10/6 = 5/3 = 1 2/3.

Lastly, let's solve the third problem.

For the third problem, 8 5/12 can be converted into the improper fraction (8*(12) + 5) / 12 = 101/12. And 1 1/2 becomes (1*(2) + 1) / 2 = 3/2.

Performing subtraction, 8 5/12 - 1 1/2 = (101/12) - (3/2) = (101/12) - (18/12) = 83/12.

To simplify this fraction, divide the numerator and denominator by their greatest common divisor (GCD), which is 1 in this case.

So, 83/12 cannot be simplified further, and it remains as 83/12.

Therefore, 8 5/12 - 1 1/2 = 7 1/3.