Gwyn earned $36 walking 4 dogs one time each. She divides to find that she earned $9 per walk. Which equations can she use to check her calculation? Check all that apply. 9 + 9 + 9 + 9 = 36 9 × 4 = 36 9 × 9 = 81 36 – 9 – 9 – 9 – 9 = 0 36 – 9 = 27