1/3 * 6/7 - 1/7 * 3/4
1/3 * 6/7 - 1/7 + 3/4 = 3/28 1) 1/3 * 6/7 = 2/7 2) 2/7 - 1/7 = 1/7 3) 1/7 * 3/4 = 3/28