Topic 7

Front

What are compatible numbers?

Back

Compatible numbers are numbers that are easy to compute with mentally. They are often rounded numbers that make calculations simpler.

Front

How do you estimate the total minutes of exercise for 42 days if puppies are exercised 25 minutes a day?

Back

You can estimate by using compatible numbers: 25 minutes can be rounded to 20 or 30, and then multiplied by 40 (the number of days) to get an estimate.

Front

What is the multiplication problem to find the total number of toothbrushes if there are 10 boxes with 15 toothbrushes each?

Back

10 boxes x 15 toothbrushes = 150 toothbrushes.

Front

How can you represent multiplication visually?

Back

You can draw an array, which is a set of rows and columns, to show how many items are in total. For example, 10 boxes of 15 toothbrushes can be shown as 10 rows of 15.

Front

What is the best estimate for the total weight of 49 boxes of paper if each box weighs about 28 pounds?

Back

The best estimate is 49 boxes x 30 pounds (rounding 28 to 30) = 1470 pounds, which can be rounded to 1500 pounds.

Front

How do you calculate the total minutes Margaret walks in a month with 31 days if she walks 30 minutes each day?

Back

30 minutes/day x 31 days = 930 minutes.

Front

What is the total number of chairs in a section with 5 rows of 5 chairs each?

Back

5 rows x 5 chairs = 25 chairs.

Front

How do you find the total number of chairs in two sections with different arrangements?

Back

Add the total from each section: 25 chairs (5 rows of 5) + 16 chairs (8 rows of 2) = 41 chairs.

Front

What is the purpose of drawing an array in math problems?

Back

Drawing an array helps visualize multiplication and addition, making it easier to understand the total.

Front

What is the multiplication problem to find the total weight of 49 boxes if each box weighs 28 pounds?

Back

49 boxes x 28 pounds = 1372 pounds, but for estimation, we round to 30 pounds.