Complete the following number patterns.
- 833, 744, 655, , 477
- 21, 31, 42, 54, .
- 152, , 171, 177, 181
(a)
833 - 744 = 89
744 - 655 = 89
655 - 89 = 566
Pattern: Keep subtracting 89 from left to right.
(b)
31 - 21 = 10
42 - 31 = 11 (1 is added to 10)
54 - 42 = 12 (1 is added to 11)
12 + 1 = 13
54 + 13 = 67
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
181 - 177 = 4
177 - 171 = 6
171 - 8 = 163
163 - 11 = 152
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 566; (b) 67; (c) 163
