1 7/8 * 0,4;

1. Convert 0.4 to a fraction: 0.4 = 4/10 = 2/5.
2. Convert the mixed number to an improper fraction: 1 7/8 = 15/8.
3. Multiply the fractions: (15/8) * (2/5) = 30/40 = 3/4.