Complete the following number patterns.
- 770, 679, 588, , 406
- 36, 45, 55, 66, .
- 131, , 149, 155, 159
(a)
770 - 679 = 91
679 - 588 = 91
588 - 91 = 497
Pattern: Keep subtracting 91 from left to right.
(b)
45 - 36 = 9
55 - 45 = 10 (1 is added to 9)
66 - 55 = 11 (1 is added to 10)
11 + 1 = 12
66 + 12 = 78
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
159 - 155 = 4
155 - 149 = 6
149 - 8 = 141
141 - 10 = 131
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 497; (b) 78; (c) 141
