The Southeast Asia Mathematical Olympiad (SEAMO) is an international Math Olympiad competition that originated in Singapore and was founded by Mr. Terry Chew in 2016 in 8 Southeast Asian Countries. Since then, it is growing its popularity around the world. In 2019 it was recognized by 18 countries. In 2020 total number of participating countries increased to 22, including students from Indonesia, Brazil, China, Newzealand, and Taiwan students enrolled in SEAMO 2022-23.

**Problem and Solution SEAMO 2021 paper A**. Soal ini bersumber dari seamo-official.org

1. Find the sum of

\(11 + 12 + 13 + โฏ + 17 + 18 + 19\)

(A) 120

(B) 125

(C) 130

(D) 135

(E) 140

2. Find the number of cubes in the figure below.

(A) 12

(B) 13

(C) 14

(D) 15

(E) 16

3. Find the missing numbers ๐ and ๐.

(A) 7 and 8

(B) 8 and 9

(C) 8 and 8

(D) 7 and 9

(E) 10 and 3

4. This year, Grandpa is 56 years old, Dad is 31 years old, and I am 7 years old. In how many years will the sum of our ages be 100?

(A) 1

(B) 2

(C) 3

(D) 4

(E) 5

5. Find the missing number.

\(2, 2, 4, 6, 10, 16, (ย ), 42\)

(A) 24

(B) 25

(C) 26

(D) 28

(E) 30

6. Which of the following comes next?

7. Wattaria is putting coins along the 3 sides of the triangle, such that there are 6 coins on each side of the triangle. How many coins are there in total? Use the figure provided to help you.

(A) 15

(B) 16

(C) 17

(D) 18

(E) 19

8. There are 18 children in a party. Each girl gets 5 balloons, while each boy gets 3 balloons. If 72 balloons are given out in all, how many boys are there?

(A) 6

(B) 7

(C) 8

(D) 9

(E) 10

9. Fill in each circle with a number from 2, 5, 6 and 7, such that the sum of the 3 numbers along each line is 18. What is ๐?

(A) 2

(B) 5

(C) 6

(D) 7

(E) None of the above

10. Postman Pat is delivering a parcel from Point ๐ด to Point ๐ต , where his movements can only be in the directions โ and โ . How many different paths can he take?

(A) 33

(B) 34

(C) 35

(D) 36

(E) 40