To find the total number of tubes of paint the teacher bought, we need to multiply the number of packs (4) by the number of tubes in each pack (18). The two correct equations that represent this situation are:
- 4 × 18 = 72 (This directly calculates the total number of tubes.)
- 18 + 18 + 18 + 18 = 72 (This adds together the number of tubes in each pack.)
The other options are not correct for this scenario.
So, the two equations that apply are:
- 4 × 18 = 72
- 18 + 18 + 18 + 18 = 72