(10 - 7 / 55 × 1) + (9 - 7 / 55 × 1) + (8 - 7 / 55 × 1) + + + + (1 - 7 / 55 × 1) 어떻게 간단하게 계산 합 니까?

(10 - 7 / 55 × 1) + (9 - 7 / 55 × 1) + (8 - 7 / 55 × 1) + + + + (1 - 7 / 55 × 1) 어떻게 간단하게 계산 합 니까?

(10 - 7 / 55 × 1) + (9 - 7 / 55 × 1) + (8 - 7 / 55 × 1) + + + (1 - 7 / 55 × 1)
= 10 / 55 - 7 / 55 + 9 / 55 - 7 / 55 + 8 / 55 - 7 / 55 + 1 / 55 - 7 / 55
= [(10 + 1) × 10 은 2] / 55 - 7 / 55 * 10
= 55 / 55 - 70 / 55
= 1 - 14 / 11
= - 3 / 11