Division usingbasicfacts by dRf7S79z

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									Division: Part A (Dividing with basic facts, with and without remainders)
(A6: demonstrate (with & without concrete materials) and understanding of ÷ (3digit by 1digit) &
remainders)

Big Idea: the inverse of multiplication
   - when we divide a number or group of things into equal parts
   - e.g. your mom bakes a dozen muffins and there are six of you, how many muffins will you
      each get

Related Vocabulary: quotient, front-end estimation (rounding), estimate, multiplication, division,
dividend, divisor

Model: Division is the inverse of multiplication.
http://www.harcourtschool.com/glossary/math2/index5.html


See the following link for an introductory lesson: showing where we are going
http://www.learnalberta.ca/ Grade 5 / Mathematices/ Division of Whole Numbers lessons

Lesson: (adapted from Saxon Math) We will use basic facts that you already know to help us getting
ready for complicated division questions. Look at two ways you see basic multiplication facts
written:

1) 2 X 4 = 8

2) 4
  X2

3) 4(2)

You will also see division questions written different ways. Here are three of them:

1) 8 ÷ 2 = 4

2) 8/2

    _ 4_
3) 2) 8

These numbers all have names. For example,

…..in the equation 2 X 4 = 8    factor X factor = product

If we know one factor, we can find out the other factor. For example,

….. 2 X ? = 8             ?X4=8

The process of finding a missing factor is called division.




                                                                                                     1
                                                   _ 4_             * the 2 is now called the divisor
8÷2=4              or as we will be writing it,   2) 8              ** the 8 is called the dividend
                                                                    *** the answer (4) is the quotient
If we know that the product is 8 and one factor is 2, then we are asking “2 times what number
equals 8? ” Since we know our multiplication facts, we know that the missing number is 4. A
division problem is like a miniature multiplication table. Do you see where the factors are?

                                0 1     2    3    4    5    6    7    8
                            0   0 0     0    0    0    0    0    0    0
                            1   0 1     2    3    4    5    6    7    8
                            2   0 2     4    6    8    10   12   14   16
                            3   0 3     6    9    12   15   18   21   24
                            4   0 4     8    12   16   20   24   28   32
                            5   0 5     10   15   20   25   30   35   40
                            6   0 6     12   18   24   30   36   42   48
                            7   0 7     14   21   28   35   42   49   56
                            8   0 8     16   24   32   40   48   56   64

Practice: Let’s solve the following orally. Please watch where we write our answer.

check out http://www.rainforestmaths.com/ (grade 5 > division)

How many times does the divisor go into dividend for each question below?
 ____                    _____                          _____                   _____
2)12                   3) 6                            7)21                    5)25


These work out nicely! Here we have our original division question. We have 8 stars divided neatly
into groups of 2.


                  We can divide our 8 stars into equal groups of 2.

                  4_
                2)8
                  8_     (We write the product of 2 X 4 just below our 8. As you can see,
                  0       we have nothing left over.


Practice:

 ____            _____               _____              _____          _____           _____
3)12           2) 6                 8)24               5)35           7)63           8)72




                                                                                                         2
However, sometimes the number inside is not an even product and we discover that we have a
remainder, something left over.

               Here we have 9 stars. If I want to divide them into groups of 2, we will have 1
               remaining.



                            We can divide our 8 stars into equal groups of 2 but then we have 1
               left over.

                                     4_
                                   2)9
                                     8    (Again, we write the product of 2 X 4 just below the 8.
                                     1     However, this time we have 1 left over, the
                                           remainder)

               We write our final answer the following way:

                                     4 r 1_
                                   2)9
                                     8 .
                                     1

view http://www.ronblond.com/MathGlossary/ (see division)

and http://new.learnalberta.ca/content/memg/Division02/Divide%20-%20Division/index.html

Some more practice………

check out http://www.rainforestmaths.com/ (grade 5 > division > 2 digit with remainder)

In pairs (someone beside or near you), estimate the following (without a remainder).

 ____                   _____                             _____                   _____
2)13                  3) 11                              7)25                    5)24




 ____                   _____                             _____                  _____
4)7                   6)13                              9)29                    8)35

                                                                                                    3
Lock Down What You Know: Rewrite the following questions and solve. Remember to line up
your place value columns and write your numbers in the correct spot. This activity is just to let you
practice what you already know.



a) 14 ÷ 7 =                           b) 24 ÷ 8 =                        c) 34 ÷ 4 =




d) 69 ÷ 8 =                           e) 36 ÷ 9 =                        f) 24 ÷ 7 =




g) 37 ÷ 5 =                           h) 49 ÷ 7 =                        i) 85 ÷ 9 =




                                                                                                    4

								
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