In cross method ++ is equal ? _ +?

When two ratios are set equal to each other, forming a proportion, like $\frac{a}{b} = \frac{c}{d}$, the cross method involves multiplying the numerator of one ratio by the denominator of the other. This gives the equality:

$$a \times d = b \times c$$

In this context, there isn't a direct "++" operation that is typically equated to something.

When adding two fractions (ratios) like $\frac{a}{b} + \frac{c}{d}$, the "cross method" is used to find a common denominator and combine the numerators.

$$\frac{a}{b} + \frac{c}{d} = \frac{(a \times d) + (b \times c)}{b \times d}$$

In this case, the "++" in your question likely refers to the sum of the cross products in the numerator:

$$\text{++} = a \times d + b \times c$$

And the denominator would be $b \times d$.

So, if you are referring to the addition of two ratios $\frac{a}{b}$ and $\frac{c}{d}$ using the cross method:

$$\frac{a}{b} + \frac{c}{d} = \frac{ad + bc}{bd}$$

Here, the "++" would be equal to the numerator, which is the sum of the cross products.

The final answer is $ad + bc$.