Quick & Easy Calculations to Save Money while Shopping

On my recent visit to a supermarket, I realized the struggle and decision making fatigue which shoppers go through while making their household purchases.

I decided to write this post to ease this struggle to the best of my capacity.

For ease of understanding I’ve made categories based on the type of decisions we need to make.

Comparison Shopping

All the examples given below are from the items I picked up from the grocery section of the supermarket.

1st comparison 

  • 24 mangoes for Rs.699
  • 72 mangoes for Rs.1899

To compare these options, first thing you do is round off the numbers.

  • 24 mangoes for Rs.699 700
  • 72 mangoes for Rs.1899 1900

After that, you need to compare the price by making the quantity same. Ideal way is to scale up the lower quantity.

In this case if you multiply smaller quantity, i.e. 24 by 3 you get 72.

Hence 24×3 mangoes in 1st case will be Rs.700×3 = Rs.2100

Where in 2nd case, 72 mangoes are available for Rs.1900

So you know, if you can consume 72 mangoes, it’s available at a bargain. However, we need to consider the perishable nature of mangoes and the quantity we can consume in a reasonable time till which mangoes can remain fresh. 


2nd Comparison

  • 85 gm of honey for Rs.149
  • 200 gm of honey for Rs.299

Again, 1st thing is to round off the prices.

  • 85 gm of honey for Rs.149 150
  • 200 gm of honey for Rs.299 300

Next, easier thing to do in this case will be to scale it up and see.

If we multiply the smaller quantity by 2, we get

85×2 = 170 gm for Rs.150 x 2 = Rs.300

Comparing once again,

In 1st case, we get 170 gm for Rs.300

In 2nd case, we get 200 gm of Rs.300

Thus clearly 2nd case is more beneficial.


3rd comparison

  • 5kg of detergent powder for Rs.153
  • 4kg of detergent powder for Rs.418 plus a bucket free.

We need to scale up the smaller quantity to match the larger quantity. Then the price comparison will be apple to apple. That too of the same size.

In the above case you saw that just simple multiplication was good enough to do that. However, here you need to do some quick thinking.

You remember HCF taught in school? Don’t panic. No worries even if you don’t.

HCF or highest common factor means finding a number which divides both the numbers.

Let me explain this for the above example. If we have smaller packets of 500 gm each, for buying 1.5 kg you need 3 packets and for buying 4 kg you need 8 packets.

So now, if 1.5kg is at Rs.153, 1 packet of 0.5kg is for Rs.153/3 = Rs.51

Therefore, 8 packets (i.e. 4kgs) will be for Rs.51*8 = Rs.408.

So, if you ignore the free bucket available you’re better off buying the smaller packet i.e. of 1.5 kg compared to 4 kg pack.

However, getting a bucket by paying additional Rs.10 is not a bad deal. So you should go for 4 kg packet.

In an earlier article I’ve touched upon calculations of gross margin, cost and sale price. That article will also help you in calculations of discounts. Have a look.

I hope I helped you to overcome your dilemma during shopping when you are spoilt for choices and one offer seems to be better than the other.

Did you all like my tips? If yes, write in the comments below. Stay tuned for another set of situations on Discount Shopping.

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