Lockdown Day 97 – Operating with Money
Numeracy and Arithmetic
Last week in lockdown tip #90, we introduced you to the concept of money, exploring it through the lens of our South African currency. In our lockdown post #55, we worked with simple addition and subtraction, and lockdown top #83 to division.
Today we will bring together these concepts together. We will ‘operate’ with money, using the skills we have learned in addition, subtraction and division, and introduce the idea of multiplication.
Using the R10 note as the base for this lesson, remind the child of its value. If necessary, repeat some of the manipulations, exchanging 2 x R5 coins, or 10 x R1 coins. This indirect preparation should not be hurried. Give your child time to assimilate these substitutions.
*ADDITION*
Simple addition can be done by using the coins to work out what R5 added to R5 equals.
You may wish to write out what was verbally asked to start the process of recording. R5 + R5 = R10.
You can also work with the addends differently by saying, I have R5, how many more Rand do I need to equal R10?
The child can then, with the R1 coins ‘count on’ until s/he reaches R10. Again, this can be written as R5 + ? = R10. This kind of computation should only be done with older children who have already grasped the initial addition well.
You can add a word problem to this work to extend the lesson. For example: If I have R2 and you have R5, how many Rand do we have?
*MULTIPLICATION*
As multiplication is actually an extension of addition, this would be a good time to introduce this operation.
Let us take R2 added to R2 added to R2 added to R2 added to R2. We can say this as it is written here as R2 + R2 + R2 + R2 +R2 or we can simplify this as R2 taken 5 times.
The child has had concrete experience here of ‘taking’ the R2 five times and thus understands the idea of the simplification to R2 times 5 equals R10. We record this using the ‘x’ symbol. R2 x 5 = R10.
A word problem here may be: If three children each have R2, how many Rand do they have altogether?
*SUBTRACTION*
Using the R10 note ask the child to take away R1. This may prove difficult as we cannot slice off a part of the note itself.
Changing the R10 note for smaller money should not pose a problem for the child who has understood the previous lessons well. Be patient with the child who first wants to exchange the R10 not for two R5 coins, and then the R5 coin for five R1 coins.
This ‘extra’ effort is the child’s mathematical mind making sense of the exchanges and needs a lot of concrete exposure before abstraction and a ‘simpler’ way can be found.
Resist the temptation to intervene at this point and show ‘an easier way’. The child who discovers the easier way for themselves will really understand the concept.
Word problem: You buy a bar of soap for R5 and pay with a R10 note. How much change will you get?
*DIVISION*
Simple division, staying with the R10 note as the base, will be a natural progression from subtraction, because, again, there will need to be an exchange of coins in order to divide them.
The child may be asked to share the R10 between 2 people. Allow for the note to be exchanged as the child sees fit and prompt only where necessary.
For example, if the child takes the five R2 coins to substitute for the R10, s/he will see that s/he cannot share them equally between the two people. S/he will be left with a single R2 coin after having given each person two of the R2 coins.
If needed ask the child if the left over R2 could be further reduced. Two R1 coins can be taken to share equally between the two people. Each person now has an equal number of Rand.
Word problem: You have R10 to share between two people. How many Rand does each person receive?
*WORD PROBLEM COMPILATION*
Ultimately, you can build up to a word problem that encompasses all operations and really stretches the child’s learning opportunity.
Mum has asked you to go to the store and buy four pies that cost R2 each. How much money will you need? (Addition or multiplication). How much change will you get if you pay the store owner with a R10 note? (Subtraction) How many pies will you and mum be able to share between the two of you? (Division)
We have kept these suggestions simple, using the base of R10, but as your child’s confidence grows, you will naturally extend the base to using the R20.00 note and further.
We hope that you will enjoy these investigations with your child!
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