218,457 to the nearest hundred thousands

12 houses are left to be sold.

Step-by-step explanation: The starting number is 80 units of houses. Last month, 2/5 of them were sold which means, houses sold last month were

Houses sold = 2/5 x 80

Houses sold = 32

If 32 houses were sold, then the houses left over were 80 - 32 which equals 48.

This month, 3/4 of the remaining houses were sold which means 3/4 of 48 houses.

Houses sold = 3/4 x 48

Houses sold = 36

If out of the remainder of 48 houses, 36 were sold, then houses left over would be

Left over = 48 - 36

Left over = 12.

Finally, there were 12 houses left to be sold