Leah put 21 white marbles. 31 black marbles. and 7 blue marbles in a bag. then her sister added 19 yellow marbles. write a number sentence to show the number of marbles in the bag

Antonio made a scale model of a building. the model's scale is 1 inch to 235 feet and its height is 3.5 inches. what is the exact height of the actual building? enter your answer in the box.

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Which of the following is the sum of 3 1/6 + 6 3/8?