#### Lesson Plan of Distributive Law

#### Mathematics Grade V

#### Students’ Learning Outcomes

*·*

*Verify distributive laws*

*Information for Teacher*

*·*

*Distributive law collects multiplication and addition subtraction operations:*

*o*

*Distributive law w.r.t addition x(b + c) = a × b+ a*

*c*

*o*

*Distributive law w .r.t subtraction ax(b – c) = a × b – a x c*

*·*

*While teaching the lesson, also consult textbook at all steps where and when applicable.*

*Material / Resources*

*Chalk/marker, board, textbook, duster*

*Worm up activity *

*·*

*Write ‘Distributive Laws” on the top of the board.*

*·*

*Ask students if they have any idea what it is?*

*·*

*Tell students that this law (sometimes called property )states that you get the same answer when you multiply a number by a group of numbers added together as when you do each multiplication separately.*

*Example: 3x (2+4) =3×2 +3×4 so the “3” can be “distributed” over the “2+4” into 3 times 2 and 3 times 4.*

*·*

*Show it with help of the following figure:*

*3 x (2 + 4) (3 x 2) + (3 x 4)*

*Development*

#### Activity 1

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*Draw the following shape on the board and tell students that this figure represents the area of rectangle with length b + c and width a*

*·*

*Hence area of this rectangle is = a x ( b + c) or a(b + c)*

*·*

*This can be split into two parts as follows:*

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*Now the sum of the area of both rectangles is a b + ac*

*·*

*Because both are parts of that rectangle, so we can write: a( b + c) = a b + ac*

*·*

*Give paper strips to students in groups to verify it for themselves.*

*Activity 2*

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*Tell students that it is very convenient to use distributive law for quick multiplication.*

*·*

*Tell students that I want to multiply 12 x 19, and I used a quick method to do it. I multiplied 12 by 20. Well 12 x 20 is easy, it’s 240. But, I added one more 12 than I needed, so I’ll take it away from 240 to give me 228. =*

*·*

*Similarly as students how to do*

*·*

*Solve 2 more examples1: 4 x 27*

*= 4(20+ 7)*

*= 4(20) + (7)*

*= 80 + 28 = 108*

*Example 2: obtain 4 x 102 using distributive law*

*Solution: We know, 102 = 100 + 2*

*So, 4 x 10 = 4 x (100 + 2)*

*= (4 x 100) + (4x 2)*

*= 400 + 8 = 408*

*Activity 3*

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*Now divide students in two groups.*

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*Each group will suggest a multiplication sum like given in the examples of previous activity, for the other group as challenge.*

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*Other group will solve in their notebooks.*

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*Each group will solve at least 5 questions.*

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*Help students if they are unable to do any question.*

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*These multiplication sums can be selected from textbook exercise as well.*

*Sum up / Conclusion*

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*The distributive laws lets you multiply a sum by multiplying each added separately and then add the products.*

*·*

*Quick multiplication can be done through distributive laws.*

*·*

*The distributive property helps with mental math.*

*·*

*A quick multiplication is:*

*4 x 53*

*= (4 + 50) + (4 x 3)*

*= 200 + 12 = 212*

*Assessment*

*·*

*Students will be given following statement questions to apply their understanding of Distributive Law.*

*·*

*Mother prepared 12 bags of sweets for birthday party of Semi. In each bag she puts 5 chocolate and 14 candies. How many sweets did mother buy?*

*·*

*A necklace made of alternating 4 grey beads and 2 black beads is shown. Explain the way one can find, how many beads are there in the necklace?*

*Follow up*

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*Solve following questions by applying Distributive Laws.*

*1.*

*In each fish tank there are 7 gold fish and 6 black fish. There are 8 fish tanks. How many fish are there altogether?*

*2.*

*There are 3 tables. On each table there are 6 lemons glasses and 5 cold drink bottles. How many drinks are there altogether?*

*3.*

*Assign some questions from textbook to do as homework.*