Numeracy Skills You Need in Real Life

Numeracy skills are the ability to handle numbers, including the basic skills of addition, subtraction, multiplication, division, percentages, and graphs.

How often do we come across such seemingly attractive sales offers?

• Buy one get one free.
• Buy a pack of 5 for Rs 80 and another of 2 packs of 6 each for Rs. 200.
• A pack of cereal or vegetable oil at a reduced rate than a branded one.
• Two packs valued at Rs xx for 100 gm. and Rs. Xxx for 2 kg.
• Prices labeled something like Rs. 103 plus VAT, Vat @ 15%.

Do we pull out our calculators in such situations? Not really, we call on our numeracy skills to remove any doubts and confusion arising out of such offers.

So let us look at some numeracy skills to deal with such situations.

Deal with Percentages

Goods and Service Tax (GST) is added as a percentage to the price of almost all items with certain exceptions. Some countries add sales tax (ST) and/or value-added tax (VAT) as a percentage of the cost of the items. Merchants like to show prices displayed as ex-taxes because (1) prices look lesser and (b) customers may claim the tax from tax authorities. Intending customers need to understand the actual cost to them for the purchase. The taxes are usually given as a percentage of the basic cost of the item.

In this situation, one needs to know the actual cost to him and no calculator may be available at the time. Here is where knowledge of percentages comes in handy.

Here, one needs to know the law of 10%: simply move the decimal point one place to the left. Let us take 10% of 110.50. Move decimal one place left leaves 11.05.

Now say tax (GST/VAT/AT) is 15%. Calculate 10%. Calculate half of 10%. Add price plus 10% plus 5% to get the final cost. Break 11% into 10% plus 1%.

Example:

What is the full price of something marked Rs 112.56 excluding VAT where VAT is 15%?

You can work out 10% of Rs. 112.56 as Rs. 11.256, so 5% is half that, which is Rs. 5.628.
Add price plus tax as 112.56 + 11.256 + 5.628 = Rs. 129.444 or 129.40 round off.
It is also useful to round up the figures. For example, if the cost of a shoe in a Bata store is Rs.899.00 then round it up to 900. Now it becomes simpler to make mental calculations quickly.

Drill down to price per unit

Merchants/Malls sometimes display/provide information on the cost of their goods in formats making it harder to compare per-unit prices. Examples are:

1. The same product displayed one place per 100 gm. and another place per kilogram.
2. Not giving the per-unit cost but advertised as Buy one get one free or Buy 2 and get 3 free offer.
3. Container volume is different but the price is indicated per 100 gm.
4. Priced one pack at 5 for 400 and two packs of 6 for 1000.
5. The merchant’s brand is priced lower than a Branded one.

Again calculators – alas not available. But the skill you need is to dig down to the cost of a unit (e.g. 100 gm., 1 item, 100 cc), which would clarify each item’s actual cost.

Let us take example 4 above. 5 for 400 means one unit cost as 400 divided by 5 = 80. Now in the second offer, we get 12 units so that cost is 12 x 80 i.e. 960. The second offer looking so good is 40 rupees costlier.

Again rounding up the cost and then working out would be a good way to get the results.

Understand those Misleading Statistics

Misleading data scaling: In the figures below there is a small difference in the data values. However, deliberate misleading data scaling in the left figure presents the difference as very large to our eyes.

Selective data picking. Deliberate and selective picking of only a small sample of data for wrong representation of facts. The left side shows only a small selection of data. Full data on the right side shows the facts.

Use of inappropriate graphs, for example, using pie charts instead of bar charts. The left side is misleading. Pie charts are used to explore different parts of one whole. Here three different entities are being depicted so using a bar chart is appropriate.

Conclusion:

Parents everywhere repeatedly try to guide their children to acquire worldly mathematical skills. Like if the value of one unit of a vegetable or fruit or milk is X, then what would be the value for a 1.5 or 2.0, etc. units. Numerical skills are a must for integrated learning so as not to fall into trap of misleading or confusing offers from the merchants.

Reference and further reading:
1. https://en.wikipedia.org/wiki/Numeracy
2. https://www.skillsyouneed.com/num/real-world-math.html