Answer:
8 cookies were left after the bake sale .
Explanation:
As given
noah was assigned to make 64 cookies for the bake sale he made 125% of that number 90% of the cookies he made were sold .
125% is written in the decimal form .

= 1.25
Total number of cookies made by noah = 1.25 × Total number of cookies assigned to make .
Putting all the values in the above
= 1.25 × 64
= 80
As given
90% of the cookies he made were sold .
90% is written in the decimal form .

= 0.90
Number of cookies were sold = 0.90 × Total number of cookies made by noah .
= 0.90 × 80
= 72
Thus
Number of cookies left = Total number of cookies made by noah - Number of cookies were sold .
= 80 - 72
= 8
Therefore the 8 cookies were left after the bake sale .