Is the set of real numbers closed under addition?

How many millimetrs are there in 4cm?

Which operation will "undo" subtraction? addition subtraction multiplication division

Joani has some stuffed animals. She has 2 times as many as Lily. Lily has 6 stuffed animals. Joanie gave 2 away and bought 4 more.

If 10% of a number is 7, what is 80% of the number?

The sum of 2 consecutive numbers is 37. Find the numbers.

What is the end behavior of the function f (x) = 2x^4 + 3x^3 - 9x^2 + 65x - 586?

I'm trying to solve 2x^2+3x=2

Suppose that a company claims that its batteries last 240 hours on average. It took many large samples, and each time the mean number of hours was outside the 95% confidence interval.

Sam added two fractions together and got 7/8 as the answer. Write down two fractions that Sam could of added.

A sign language club made $627.50 from selling popcorn at a festival. The popcorn cost the club $95.00. Which expression represents the amount of money that was raised for each member of the club?