If 3 trees have 986 leaves, how many leaves are there in 7 such trees?

Given that there are 986 leaves in 3 trees, we can find the average number of leaves per tree by dividing the total number of leaves by the number of trees.

$$\text{Leaves per tree} = \frac{986 \text{ leaves}}{3 \text{ trees}}$$

To find the total number of leaves in 7 trees, multiply the leaves per tree by 7.

$$\text{Total leaves in 7 trees} = \left(\frac{986}{3}\right) \times 7$$ $$\text{Total leaves in 7 trees} = \frac{986 \times 7}{3}$$ $$\text{Total leaves in 7 trees} = \frac{6902}{3}$$

The total number of leaves in 7 trees is $\frac{6902}{3}$. This can also be expressed as a mixed number: $2300 \frac{2}{3}$ leaves.

The number of leaves in 7 such trees is $\boxed{\frac{6902}{3} \text{ leaves}}$.