18 – 5 = 13 (denk aan 8 – 5 = 3)
16 – 6 = 10
15 – 4 = 11
18 – 10 = 8 (10 – 10, 'k wil je nooit meer zien)
16 – 10 = 6
12 – 10 = 2
19 – 16 = 3 (19 – 10 = 9, 9 – 6 = 3 en 10 – 10, 'k wil je nooit meer zien)
15 – 11 = 4
20 – 16 = 4 (20 – 10 = 10, 10 – 6 = 4)
20 – 12 = 8
20 – 6 = 14 (denk aan 10 – 6 = 4)
20 – 3 = 17
20 – 9 = 11