How do I know when to divide multiply add or subtract in a math word problem

Anna cut two pizzas into eighths. she ate 1/4 of a pizza on Friday, and three slices on Saturday. What fraction of the two pizzas are left.

Which of the following is equivalent to 18-V-25?

What are the next 4 numbers in the pattern below 20, 15, 10, 5

Find the value of c that will make 9x2 + 30x + ca perfect square trinomial.

What's 8/9x + 276 3/7^2

To decrease an amount by 23%, multiply by?

A garden (60 ft x 40 ft) is surrounded on all sides by a 5 foot walkway. What is the area of the garden? What is the area of the walkway? What is the perimeter along the outer edge of the walkway?

Josh cut a square sheet of paper along a diagonal to make two congruent triangles. The area of one triangle is 60.5 in." Find the length of one side, s, of the square. Show your work.

In a random sample of cars driven at low altitudes, of them exceeded a standard of grams of particulate pollution per gallon of fuel consumed. In an independent random sample of cars driven at high altitudes, of them exceeded the standard.

Suppose you do a favor for 3 people. then you ask each of them to do a favor for 3 more people, passing along the request that each person who receives a favor does a favor for 3 more people.