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Meet bonny and tommy

Educator section


Leaner section


Activity: rounding off [lo 1.8, lo 1.10]

  • Get some counters from your teacher. Estimate how many you have. Write down your estimate.

I estimate ____________________________________________________________

  • Now group the counters on the desk in tens and units.
  • Count them and write: I have ______________________________________
  • How was your estimate: too many, too few or just right?

Write: I estimated ________________________________________________

By how many were you out? _____________________________________________

  • Is your number closer to 40, closer to 50 or equally far away from both?

Write: My number is ___________________________________________________

  • How can you make your number equal to 50?

Write: I can add _______________ ____________ + ____________ = 50

  • If you have added 5 or less than 5, 50 is your nearest multiple of ten.
  • How can you make your number equal to 40?

Write: I can subtract _______________ : ____________ - ____________ = 40

  • If you subtracted 4 or less than 4, then 40 is your nearest multiple of ten.
LO 1.8

To round off a number to the nearest ten you must know which multiple of ten is closer to the number. If your number is the same distance from two multiples of ten, we use the greater multiple of ten.

  • Look at the numbers and make an * next to the nearer multiple of ten.
43 40 50
49 40 50
46 40 50
41 40 50
LO 1.10
  • Now help Bonny and Tommy to find the nearer multiple of ten.

Remember: If the units are 5 or more than 5,

we use the greater multiple.

  • If the units are 4 or less than 4, we use the smaller multiple.

24: nearer multiple is 20 16: nearer multiple is 20

37: nearer multiple is _____ 52: nearer multiple is _____

15: nearer multiple is _____ 73: nearer multiple is _____

81: nearer multiple is _____ 94: nearer multiple is _____

  • Round off to the nearer 10. (This will help you to estimate):

If we round off, it helps us to estimate what the answer should be more quickly.

Remember! This is not an accurate answer!

  • Use rounding off and estimate first. Then do an accurate calculation. Write the rounded off number above the number.
  • Tommy has 84c in his purse and buys a banana for 69c.

How much money does he have left?

Rounding off: Number sentence: _____________________________________________________________________

Calculate: Number sentence: _____________________________________________________________________

This will help you to estimate your change when you buy something.

LO 1.10
  • Bonny prefers to do her sums horizontally.
  • Tommy prefers to do his sums vertically.
  • Let’s try both ways and then decide which is the easier.
LO 1.8

Bonny says: Subtraction is a bit different.

  • NEVER rename the first number.

Check your answer: 12 + 64 = 76

  • Like this! He thought like this:
  • Check your answer:

1 2



  • What do you think, do you want to do your sums like Bonny or like Tommy?


LO 1.8


Learning Outcome 1: The learner will be able to recognise, describe and represent numbers and their relationships, and to count, estimate, calculate and check with competence and confidence in solving problems.

Assessment Standard 1.8: We know this when the learner can perform calculations, using appropriate symbols, to solve problems involving:

1.8.1 addition and subtraction of whole numbers with at least 3 digits;

1.8.2 multiplication of at least whole 2-digit by 1-digit numbers;

1.8.3 division of at least whole 2-digit by 1-digit numbers;

  • estimation;

Assessment Standard 1.10: We know this when the learner uses the following techniques:

1.10.1 building up and breaking down numbers;

1.10.2 doubling and halving;

1.10.3 number-lines;

1.10.4 rounding off in tens.

Questions & Answers

I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Mathematics grade 3. OpenStax CNX. Oct 14, 2009 Download for free at http://cnx.org/content/col11128/1.1
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