Hey there!
Since there are 640 muffins everyday, and there are 7 days in a week, you can use the equation " 640 x 7" to find out how many muffins the bakery makes in a week.
640 x 7 = 4,480
The bakery makes 4,480 muffins in 1 week. <-----
Hope this helps you.
Have a great day!