This short video and interactive assessment activity is designed to teach fourth graders about estimating the number needed using remainders.

This short video and interactive assessment activity is designed to teach third graders about finding the remainder given the total number and number of groups.

This short video and interactive assessment activity is designed to teach third graders about grouping with illustrations II - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about finding the missing number.

This short video and interactive assessment activity is designed to teach fifth graders about dividing 2-digit numbers by 2-digit numbers.

Unit 5: Arithmetic in Base Ten
Lesson 13: Dividing Decimals by Decimals

In the previous lesson, students learned how to divide a decimal by a whole number. They also saw that multiplying both the dividend and the divisor by the same power of 10 does not change the quotient. In this lesson, students integrate these two understandings to find the quotient of two decimals. They see that to divide a number by a decimal, they can simply multiply both the dividend and divisor by a power of 10 so that both numbers are whole numbers. Doing so makes it simpler to use long division, or another method, to find the quotient. Students then practice using this principle to divide decimals in both abstract and contextual situations.

Unit 5: Arithmetic in Base Ten
Lesson 12: Dividing Decimals by Whole Numbers

This lesson serves two purposes. The first is to show that we can divide a decimal by a whole number the same way we divide two whole numbers. Students first represent a decimal dividend with base-ten diagrams. They see that, just like the units representing powers of 10, those for powers of 0.1 can also be divided into groups. They then divide using another method—partial quotients or long division—and notice that the principle of placing base-ten units into equal-size groups is likewise applicable.

The second is to uncover the idea that the value of a quotient does not change if both the divisor and dividend are multiplied by the same factor. Students begin exploring this idea in problems where the factor is a multiple of 10 (e.g. 8/1 = 80/10). This work prepares students to divide two decimals in the next lesson.

Unit 5: Arithmetic in Base Ten
Lesson 11: Dividing Numbers that Result in Decimals

So far, students have divided whole numbers that result in whole-number quotients. In the next three lessons, they work toward performing division in which the divisor, dividend, and quotient are decimals. In this lesson, they perform division of two whole numbers that result in a terminating decimal. Students divide using all three techniques introduced in this unit: base-ten diagrams, partial quotients, and long division. They apply this skill to calculate the (terminating) decimal expansion of some fractions.

Students analyze, explain, and critique various ways of reasoning about division (MP3).

This short video and interactive assessment activity is designed to teach third graders about dividing by 10.

This short video and interactive assessment activity is designed to teach third graders about dividing by 11.

This short video and interactive assessment activity is designed to teach third graders about dividing by 12.

This short video and interactive assessment activity is designed to teach third graders about dividing by 1 digit numbers with remainders.

This short video and interactive assessment activity is designed to teach third graders about dividing by 2.

This short video and interactive assessment activity is designed to teach third graders about dividing by 3.

This short video and interactive assessment activity is designed to teach third graders about dividing by 4.

This short video and interactive assessment activity is designed to teach third graders about dividing by 5.

This short video and interactive assessment activity is designed to teach third graders about dividing by 6.

This short video and interactive assessment activity is designed to teach third graders about dividing by 7.

This short video and interactive assessment activity is designed to teach third graders about dividing by 8.

This short video and interactive assessment activity is designed to teach fourth graders about dividing by 8.