7 6/7 * 1 9/11 + 3 1/7 * 3/11
7 6/7 * 1 9/11 + 3 1/7 * 3/11=55/7 * 20/11 + 22/7 * 3/11=5/7*20/1+2/7*3/1= =100/7+6/7=106/7=15 1/7
1)7 6/7 *1 9/11= 14 2/7 2)3 1/7 *3 /11=6/7 3)14 2/7+6/7=15 1/7