Lower Elementary:
Question: There are 4 cows, 2 dogs, 5 chickens, and 1 pig on a farm. How many legs do the animals have all together?
Answer: 38 legs
Solution: Cows, dogs, and pigs have 4 legs and chickens have 2 legs. The total number of cows, dogs, and pigs are 7 (4 + 2 + 1 = 7). The total number of legs they have is 28 (7, 4 times is 28). The chickens have a total of 10 legs (5, 2 times is 10). Together, they have a total of 38 legs (28 + 10 = 38).
Upper Elementary:
Question: Penelope baked brownies. She baked one large rectangular brownie and then cut it into pieces. Penelope cut 5 vertical lines and 3 horizontal lines. She then cut every piece in half. She ate 3 pieces of brownies. How many brownies are left?
Answer: 45 brownies
Solution: Starting with the large rectangular brownie, Penelope cuts in 5 vertical lines and 3 horizontal lines, making it a 6 by 4 grid. This means the large brownie is cut into 24 brownie pieces (6 × 4 = 24). She then cuts each piece in half, which means there are twice as many brownies now. 24 doubled is 48, so now there are 48 brownies. She ate 3 brownies, so there are 45 brownies left (48 – 3 =45).
Middle School:
Question: A bottle is 90% full of water. Half of the water in the bottle is used in a recipe. Then 15mL of water is added to the bottle. It now contains 105mL of water. How much water can the bottle hold when it is 100% full?
Answer: 200mL
Solution: The bottle starts at 90% of water. And then half of the water is used, so now it has 45% of water. 15mL were added so that it contained 105mL. That means before the 15mL were added, the bottle contained 90mL. So now we ask, “45% of what number is 90?” Percent means for each hundred. 45% of 100 is 45, so 45% of 200 is 90. When the bottle is 100% full, it can hold 200mL
Algebra and Up:
Question: Jayleen wants to have at least a 90 point average in her tests in math class. On her first 5 tests, she scored 86, 94, 90, 88, and 89. What is the minimum score she needs on her next math test to get a 90 point average?
Answer: 93
Solution: The average she wants is 90 with her 6 tests. If we multiply 90 by the total number of tests, we will know what the sum of the 6 tests should be. 90 × 6 = 540. She needs 540 as the sum of her 6 tests. Her first 5 tests, she scored 86, 94, 90, 88, and 89. The sum of these is 447. Subtract 447 from 540 to get the score Jayleen needs to get a 90 point average. 540 – 447 = 93. Jayleen needs to score a 93 on her sixth test to have an average of 90.
(925) 292-8854
