Start by putting into improper fractions.
- 1 2/3 = - 5/3
- 2 1/5 = - 11/5
Now stack the fractions like this.
Here's the key part (or one of them). Cancel the minus signs. Since there are 2 of them they become a plus.
Now invert the 11/5. That means turn it upside down. Put the 5 in the numerator and 11 in the denominator. Multiply by it by the top fraction.
When you do this, you just multiply top by top and bottom by bottom
- 1 2/3 = - 5/3
- 2 1/5 = - 11/5
Now stack the fractions like this.
Here's the key part (or one of them). Cancel the minus signs. Since there are 2 of them they become a plus.
Now invert the 11/5. That means turn it upside down. Put the 5 in the numerator and 11 in the denominator. Multiply by it by the top fraction.
When you do this, you just multiply top by top and bottom by bottom