Insert the missing number
5
19
27
89
(5 ×15) + (6 × 3) = 75 + 18 = 93
(7 × 5) + (9 × 6) = 35 + 54 = 89
(18 × 1) + (4 × 8) = 18 + 32 = 52
Insert the missing number: 4, 9, 20, 43, 90, ___