Math 6 Fluently Dividing Multi-Digit Numbers Using Base Ten Blocks Demonstrating Mastery Demonstrating Mastery – In this lesson students will fluently divide multi-digit numbers using base ten blocks.

M.6.NS.2 Students will fluently divide multi-digit numbers using the standard algorithm. Base ten blocks will be used to demonstrate the division. In this lesson the students will be using base ten blocks to model division with multi-digit numbers. This is the first step that we will use ton prepare the students for fluently dividing multi-digit numbers using the standard algorithm.

PROBLEM The school is collecting food items for the Food Drive. Each classroom is expected to bring in 250 items of food. There are 21 students in your class. How many cans of food would each student need to bring in order to meet expectations? Use the base ten blocks to help you solve the problem. By the end of the lesson, the students will be able to use the base ten blocks that are provided to solve this multi-digit problem. By now the students should know their multiplication facts and some division facts that they will need to use during this process. As for the problem, by the end of the lesson the students should be able to see that the 250 cans are the dividend and 21 is the divisor, and we are looking for the quotient. The students should be able to set up the problem numerically and with the base ten blocks.

SOLUTION In order to figure out how many each student must bring you, you must divide. With the use of base ten blocks, students can actually divide the numbers up with materials. As understanding improves, the concrete manipulatives will no longer be needed and the students should be able to do the problem using the standard algorithm.

Solution Continued 250 divided by 21 Take the 250 base ten blocks and divide by 21 Each student must bring in 12 cans because 11 cans will not be enough. Your final answer is 11 19/20. As the students’ understanding increases, the students should rely less on the manipulatives and more on the conceptual understanding. It is critical that the students see that there are certain steps that are continuously repeated. The continuous repetition should help the students with moving on to the next step.

Solution Continued 250÷21 = 11 Begin with your 2 hundreds. You can’t 21 ) 250 divide the two into 21 equal parts until you -21 break it into tens. There are 20 tens then 40 your remaining 5 tens for a total of 25 tens. -21 Now you can divide the 25 tens by 21 19 which is 1 ten in each of the 21 groups 4 tens remaining. Now you can divide 40 by 21.The answer to that is 1 so the answer is 11 with a remainder of 19. From the example, you can see that you are dividing by repeatedly following the same basic steps. During this lesson, you will see that the division of multi-digit numbers actually involves division, subtraction, and multiplication. Therefore, at the end of this lesson, you will be able to divide multi-digit numbers using the base ten blocks.

Solution Continued Your answer is 11 remainder 19. What does that mean? That means that each student must bring in 11 cans. But there is a remainder. The remainder means that 19 cans are still needed. So, we can have one person bring in all 19 or have all 25 bring in an extra can and then there will be extra.