Building the number line

=Activity - Understanding numbers, properties through number line=

Objectives

 * 1) Understanding what is a number line
 * 2) Understanding properties(behaviour) of positive and negative numbers through number line
 * 3) Understanding number sentences /operations of numbers on the basis properties of numbers.
 * 4) Compare numbers/ordering numbers

Estimated Time
60 minutes

Materials/ Resources needed
Paper, pencils/ sketch pens

Prerequisites/Instructions, if any
Students know about numbers,Numbers are continuous, counting, quantities for ex: difference between 2 books,2 kgs of apples or 2 litres of milk,2 mts ..... Please emphasise that positive numbers increase the quantities and negative numbers decreases the quantity(amount)

Step 1

 * 1) Ask boys to write positive number and girls to write negative numbers on a sheet of paper. Each one should write one number. Instruct them to arrange the numbers in order on the floor.
 * 2) Now ask boy and girl to come one after other to keep the number which they have written.
 * 3) Suppose the first boy comes and keeps +5 then call other girl ask her to keep her number.
 * 4) She can keep it anywhere she wants (imagine she has -7 on her sheet)
 * 5) But the real fun starts when the third one(boy) will come(imagine he has +10 on his sheet)
 * 6) You have to help him to keep the number in a proper order as he will have a positive number you should  guide him where he should keep it and why?
 * +5
 * -7

(+10 is more than +5) If the next girl comes with -4 ,where she should keep it? Continued pattern will be Place all the numbers what they have written on the sheet.
 * 1) If the numbers are kept as above where +10 should be placed?why?
 * 2) For this we need to explain +5 has  property of increasing  the quantity by 5 whereas -7 has a property of decreasing the quantity by -7,(+5 is more than -7) so where should be place for +10.
 * 3) +10 has a nature of increasing the quantity more than what +5 does .so keep it above +5.
 * +10
 * +5
 * -7
 * +10
 * +5
 * -4
 * -7

Step:2
Ask them
 * 1) Is there any number missed in between?
 * 2) If the answer is yes ask them again to write the missed numbers and repeat the activity by placing those numbers in a right place, which completes the number line. Now explain number line is a model for representing numbers.
 * 3) Now the number pattern will look like this after filling the gaps
 * -9
 * -8
 * -7
 * -6
 * -5
 * -4
 * -3
 * -2
 * -1
 * 0
 * +1
 * +2
 * 3
 * 4
 * 5
 * 6
 * 7
 * 8
 * 9 (You can also ask which is the last number?) The number arrangement need not be horizontal

Step:3
Now write some number sentences as below .Help them to interpret the sentences.


 * 1) 4+(+3)=+7 - The value of 4 increased to +7 when it is added to +3  (+3 increases the value of 4 by how much?)
 * 2) 4+(-3)=+1 - The value of 4 decreased to +1when it is added to -3  (-3 decreases the value of 4 by how much?)
 * 3) -4+(+3)=-1 - The value of -4 increased to +7 when it is added to +3  (+3 increases the value of 4 by how much?)
 * 4) -4+(-3)=-7 -

Developmental Questions (What discussion questions)
(-7 decrease the quantity by 7 where as -4 decrease any quantity just by 4)
 * 1) What is the behaviour of -7 and -4
 * 1) Try to extract from them that -4 is more than -7.

Activity Keywords
To link back to the concept page Numbers