0.0021 in scientific notation

What are two expression where the solution is 18

100 + 20m when m = 5 1/4

Of the 327 students in the ninth grade, 109 belong to an after-school club. What percent of the students belong to an after-school club? Show work.

Make up a word problem for y = 50+4x

Radius 19 is equal to 4.358 true or false?

Write a function for "The output is seven more than the input"

After attending a church cookout, a number of the attendees are admitted to the emergency room with nausea, vomiting, and diarrhea.

Antonio needs 8 feet of ribbon to complete a project. He can purchase a 180-inch (15-foot) packaged length for $3.99, or he can buy the ribbon by the foot for $0.39/ft. Which is the better deal for Antonio?

Edward walked 3/4mile from his home to the park. Then he walked 2/4 mile from the park to the library. which distance is shorter?

Two clocks are turned on at the same time. One clock chimes every 15 minutes. The other clock chimes every 25 minutes. In how many minutes will they chime together?