Complete the following number patterns.
- 615, 516, 417, , 219
- 25, 35, 46, 58, .
- 121, , 141, 148, 153
(a)
615 - 516 = 99
516 - 417 = 99
417 - 99 = 318
Pattern: Keep subtracting 99 from left to right.
(b)
35 - 25 = 10
46 - 35 = 11 (1 is added to 10)
58 - 46 = 12 (1 is added to 11)
12 + 1 = 13
58 + 13 = 71
Pattern: Keep adding 1 to the previous added number from left to right.
(c)
153 - 148 = 5
148 - 141 = 7
141 - 9 = 132
132 - 11 = 121
Pattern: Keep subtracting 2 from the previous subtracted number from right to left.
Answer(s): (a) 318; (b) 71; (c) 132
