Page 163 - Math Skill - 4

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Exercise 12.2

1. Write the rule of the patterns and fill in the missing numbers in each of the following.

(a) 1, 2, 3, 5, 8, 13, , , Rule: ______________

(b) 30, 35, 33, 38, , , Rule: ______________

(c) 122, 120, 115, 113, 108, 106, , , Rule: ______________

(d) 4, 12, 36, 108, , , Rule: ______________

2. Fill in the blanks to complete the following patterns.

(a) 1 + 2 = 3 (b) 111 ÷ 3 = 37
1 + 2 + 3 = 6 222 ÷ 6 = 37
1 + 2 + 3 + 4 = 10 333 ÷ 9 = 37
1 + 2 + 3 + 4 + 5 = _____ 444 ÷ ___ = 37
1 + 2 + 3 + 4 + 5 + 6 = _____ 555 ÷ ___ = ___

1 + 2 + 3 + 4 + 5 + 6 + _____ = _____ ___ ÷ 18 = 37

Hint: Last number × Consecutive number
2

3. Study the pattern and find the missing term.
(a) (b) (c)
16 10 1 4 3 2

8 2 5 2 2 3 9 5 4 7 5 3

18 ? 2 14 5 ? 13 6 4 9 ? 3

9 7 6 7 5 8

4. Study the pattern and fill in the circles.

(a) (b) (c) (d)

12 6 12 4
5 7 9 8 16 2 3 4 2 2 3
2 3 4 5 3 5 7 9 1 2 1 3

1 2 3 4 5

Secret Codes
Sometimes some information is secret. So, instead of writing it in the normal language, it is
coded by writing numbers instead of letters or different letters instead of the original letters.