If each digit can be any number from 0 to 9 how many different credit numbers are possible

What values of c and d make the equation true?

You are on a cycling trip around europe with friends. you check the weather forecast for the first week. these are the temperatures for the week. sun mon tues wed thurs fri sat 16°c 20°c 24°c 28°c 28°c 23°c 15°c what is the mean temperature forecast for the week?

Due to financial difficulties the owner of 4 skateboard stores is going to close 2 of his stores. based on the money earned at each store, which two stores should remain open?