The Simple Aggregative Method compares the sum of current-year prices to the sum of base-year prices directly.

Step 1 — Sum the prices.

$\sum p_0 = 10+8+5+12 = 35$

$\sum p_1 = 15+10+6+14 = 45$

Step 2 — Apply the formula.

Cross-check by re-adding the columns independently. Re-summing $p_0$ column-wise (10, 18, 23, 35 running total) and $p_1$ column-wise (15, 25, 31, 45 running total) reproduces the identical totals 35 and 45, confirming no addition slip before the division step.

Dividing $\sum p_0$ by $\sum p_1$ (inverting the ratio) instead of $\sum p_1$ by $\sum p_0$ — the current year always goes in the numerator when constructing a forward (base-to-current) index.