The set of natural numbers less than 8.(set builder method)​

Mp model with mathematics explain how the number of text messages dario sent and the cost form an arithmetic sequence.then write an expression to find dario's text messaging bill if he sends n text messages over 250.

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?