-1/3/10 + - 4/2/15

To add -1/3/10 and -4/2/15, we first need to find a common denominator. In this case, the common denominator is 30.

-1/3/10 = -10/30
-4/2/15 = -30/30

Now we can add the two fractions:

-10/30 + -30/30 = -40/30

Simplifying the fraction by dividing both the numerator and the denominator by their greatest common divisor, we get:

-40/30 = -4/3

To add the given fractions, we need to make sure they have the same denominator.

The first fraction is -1/3/10, which we can rewrite as -1/30.

The second fraction is -4/2/15, which we can simplify as -2/15.

Now, we can add the fractions:

-1/30 + -2/15

To add fractions, we need a common denominator. The smallest number that both 30 and 15 divide into is 30.

So, we'll convert both fractions to have a denominator of 30:

-1/30 = -1 * (30/30) = -30/30
-2/15 = -2 * (2/2) = -4/30

Now, we can add the fractions:

-30/30 + -4/30 = (-30 - 4) / 30 = -34/30

However, we can simplify the fraction by dividing both the numerator and denominator by their greatest common divisor, which is 2:

-34/30 = -17/15

Therefore, the sum of -1/3/10 and -4/2/15 is equal to -17/15.