Building the number line
Activity - Understanding numbers, properties through number line
- Understanding what is a number line
- Understanding properties(behaviour) of positive and negative numbers through number line
- Understanding number sentences /operations of numbers on the basis properties of numbers.
- Compare numbers/ordering numbers
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)
Website interactives/ links/ simulations/ Geogebra Applets
Process (How to do the activity)
- 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.
- Now ask boy and girl to come one after other to keep the number which they have written .
- Suppose the first boy comes and keeps +5 then call other girl ask her to keep her number .
- She can keep it anywhere she wants (imagine she has -7 on her sheet)
- But the real fun starts when the third one(boy) will come(imagine he has +10 on his sheet)
- 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?
- If the numbers are kept as above where +10 should be placed?why?
- 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
- +10 has a nature of increasing the quantity more than what +5 does .so keep it above +5.
(+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.
- Is there any number missed in between?
- 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 .
- Now the number pattern will look like this after filling the gaps
- 9 (You can also ask which is the last number?) The number arrangement need not be horizontal
Now write some number sentences as below .Help them to interpret the sentences.
- 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?)
- 4+(-3)=+1 - The value of 4 decreased to +1when it is added to -3 (-3 decreases the value of 4 by how much?)
- -4+(+3)=-1 - The value of -4 increased to -1 when it is added to +3 (+3 increases the value of -4 by how much?)
- -4+(-3)=-7 - The value of -4 decreased to -7 when it is added to -3 (-3 decreases the value of -4 by how much?)
Developmental Questions (What discussion questions)
- What is the behaviour of -7 and -4
(-7 decrease the quantity by 7 where as -4 decrease any quantity just by 4)
- Try to extract from them that -4 is more than -7.
Evaluation (Questions for assessment of the child)
- Students can be asked to cite examples where positive and negative numbers are used in daily life.
Ex: Money (profit/loss), Elevation
2. What do positive and negative numbers represent while dealing with money?
3. What do positive and negative numbers represent while dealing with elevation /depth?
To link back to the concept page Numbers