Problems:

$$ \sum_{i=1}^{5} 1 = 5 $$

5

$$

\sum_{i=1}^{10} 2i = 110 $$

110

$$ \sum_{i=1}^{10} (5i^2 + 3i + 2) = 2110 $$

2110

$$ \sum_{j=1}^5\sum_{i=1}^{10} 5i^2 = 9625 $$

9625

$$ \sum_{j=1}^5\sum_{i=1}^{j} (3i + 2) = 135 $$

135