Determine the price of a two-year bond with sixmonthly coupons of 10.00% per annum, a yield of 6.40% per annum and face value of $100 where the bond is purchased with 40 days to the first coupon payment and there are 181 days in the coupon period.

One of the ways of answering such question is:

The price of the bond is determined by compounding the price to the purchase date. Thus the price is: Price = $106.66 x (1.032) (181-40)/181 = $109.32

How did they get the number $106.66? Thank you :)