Letter on position 1 (w) changed: 10 words basts casts easts fasts gasts lasts masts oasts pasts vasts Letter on position 2 (a) changed: 2 words wests wists Letter on position 3 (s) changed: 6 words wadts wafts waits wants warts watts Letter on position 4 (t) changed: 3 words wases wasms wasps Letter on position 5 (s) changed: 1 word waste