Complete the following number patterns.
- 591, 501, 411, , 231
- 22, 28, 35, 43, .
- 54, , 68, 73, 76
(a)
591 - 501 = 90
501 - 411 = 90
411 - 90 = 321
Pattern: Keep subtracting 90 from left to right.
(b)
28 - 22 = 6
35 - 28 = 7 (1 is added to 6)
43 - 35 = 8 (1 is added to 7)
8 + 1 = 9
43 + 9 = 52
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
76 - 73 = 3
73 - 68 = 5
68 - 7 = 61
61 - 7 = 54
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 321; (b) 52; (c) 61
