Answer:
4 × 10 - 4 = 36 granola bars
Explanation:
4 packages with 10 bars each means 40 bars (4 packages × 10 bars each = 40 bars total)
one bar from each package
there are 4 packages so if he eats only one from each then he eats 4 bars total
40 bars total - 4 bars he ate = 36 bars left over