Complete the following number patterns.
- 781, 726, 671, , 561
- 24, 33, 43, 54, .
- 61, , 79, 85, 89
(a)
781 - 726 = 55
726 - 671 = 55
671 - 55 = 616
Pattern: Keep subtracting 55 from left to right.
(b)
33 - 24 = 9
43 - 33 = 10 (1 is added to 9)
54 - 43 = 11 (1 is added to 10)
11 + 1 = 12
54 + 12 = 66
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
89 - 85 = 4
85 - 79 = 6
79 - 8 = 71
71 - 10 = 61
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 616; (b) 66; (c) 71
