1.
5/7 * 14/25 = 2/5,
3/5 * 15 = 3 * 3 = 9,
2 1/4 * 8/15 = 9/4 * 8/15 = 6/5 = 1 1/5,
2.
5/7 от 100 = 5/7 * 100 = 500/7 = 71 3/7,
1 5/7 от 6,3 = 12/7 * 6,3 = 12 * 9/10 = 54/5 = 10 4/5,
45% от 150 = 0,45 * 150 = 9/20 * 150 = 67 1/2,
4.
4 1/9 * (2 5/8 + 1 3/8) = 4 1/9 * 4 = 37/9 * 4 = 148/9 = 16 4/9,