Question 4
A beaver tries to enter a thieves’ hideout. The guard uses Vietnamese number words. The beaver hears these accepted exchanges: “Mười” (ten) → “Bốn” (four), “Hai” (two) → “Ba” (three), and “Ba” (three) → “Hai” (two). When the guard says “Bốn” (four), the beaver replies “Mười” (ten) and is refused. What should it say to be admitted? Keep the Vietnamese words when applying the rule.