化簡67×66分之65,12分之5÷9+12分之5÷8分之9

化簡67×66分之65,12分之5÷9+12分之5÷8分之9

=(66+1)*(65/66)
=65+(65/66)
=65又65分之66
=(5/12)*(1/9)+(5/12)*(8/9)
=(5/12)*1
=5/12