Complete the following number patterns.
- 803, 721, 639, , 475
- 21, 28, 36, 45, .
- 77, , 94, 101, 106
(a)
803 - 721 = 82
721 - 639 = 82
639 - 82 = 557
Pattern: Keep subtracting 82 from left to right.
(b)
28 - 21 = 7
36 - 28 = 8 (1 is added to 7)
45 - 36 = 9 (1 is added to 8)
9 + 1 = 10
45 + 10 = 55
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
106 - 101 = 5
101 - 94 = 7
94 - 9 = 85
85 - 8 = 77
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 557; (b) 55; (c) 85
