Carol has written a number pattern that begins with 1, 3, 6, 10, 15. If she continues this pattern, what are the next four numbers in her pattern?  Explain your thinking and reasoning.

A student wants to earn a C for a class. To get this grade, the average of his six test scores must be 70. He has the following grades on five tests: 60, 78, 65, 68, 72 What grade must the student get on the next test so that the average of his scores is 70? Enter your answer as a number, like this: 42

I need help and answer key for 14 and 15

Use the Black and Red chips model to illustrate the process of obtaining -7+4= -3 . Describe each step of the process. Be specific in explaining the process.