3.4x 80% + 0.8 + 80% x 5.5 간편 연산

3.4x 80% + 0.8 + 80% x 5.5 간편 연산


3.4x 80% + 0.8 + 80% x 5.5
= 3.4 × 0.8 + 0.8 + 0.8 × 5.5
= 0.8 × (3.4 + 1 + 5.5)
= 0.8 × 9.9
= 0.8 × (10 - 0.1)
= 0.8 × 10 - 0.8 × 0.1
= 8 - 0.08
7. 92



간편 계산 7.8 * 80 + 6.5


간편 한 계산:
7.8 * 80 + 6.5
= 7.8 * (100 - 20) + 6.5
= 780 - 156 + 6.5
= 780 - 150 + 0.5
= 630 + 0.5
= 630.5%



간편 계산: (8 / 7 - 4 / 5) × 7 / 8


(8 / 7 - 4 / 5) × 7 / 8 = 8 / 7x 7 / 8 - 4 / 5x 7 / 8 = 1 - 7 / 10 = 3 / 10