Answer:
20
Step-by-step explanation:
4 * 1 = 4 5 * 1 = 5
4 * 2 = 8 5 * 2 = 10
4* 3 = 12 5 * 3 = 15
4 * 4 = 16 5 * 4 = 20
4 * 5 = 20
they both go into 20 equally. there is no number lower than 20 that they both go into
