Complete the following number patterns.
- 878, 803, 728, , 578
- 22, 31, 41, 52, .
- 56, , 74, 80, 84
(a)
878 - 803 = 75
803 - 728 = 75
728 - 75 = 653
Pattern: Keep subtracting 75 from left to right.
(b)
31 - 22 = 9
41 - 31 = 10 (1 is added to 9)
52 - 41 = 11 (1 is added to 10)
11 + 1 = 12
52 + 12 = 64
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
84 - 80 = 4
80 - 74 = 6
74 - 8 = 66
66 - 10 = 56
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 653; (b) 64; (c) 66
