Skip to content / Đến nội dung
ThichHocToan.com

SEAMO 2026 Paper A SET 4 – Self-practice Question 15

SEAMO · SEAMO 2026 Paper A SET 4 – Self-practice

Question 15

Find the value of $1+2+3+\cdots+9+10+9+\cdots+3+2+1$.
  1. 98
  2. 100
  3. 102
  4. 104
  5. 106