Viết các số sau bằng chữ số La Mã. a) 4, 9, 14

a) 4, 9, 14

4 – IV, 9 – IX, 14 – XIV

b) 5, 6, 15, 16, 17

5 – V, 6 – VI, 15 – XV, 16 – XVI, 17 – XVII

c) 7, 8, 18, 19

7 – VII, 8 – VIII, 18 – XVIII, 19 – XIX

d) 10, 11, 12, 13, 20, 21, 22, 23

10 – X, 11 – XI, 12 – XII, 13 – XIII, 20 – XX, 21 – XXI, 22 – XXII, 23 – XXIII