This is one example on how to use your smartphone calculator at stores for smart shopping.
- 6 pack of soda is $6.00
- 12 pack of soda is $13.00
What is more economical?
The answer is 6 pack of soda at $6.00 - Because you can buy two 6 packs and pay $12.00. You save $1.00 by NOT buying 12 pack at $13.
You can do this calculation in your head.
But, in the real world, stores will trick you with complicated price structures.
For example - more realistic this time.
- 4 lbs of rice is $3.75
- 9 lbs of rice is $7.95
How do I know which is a better buy?
This is when you use a calculator to figure out "Per pound" price.
When you do this kind calculation, there is one rule to remember "Money comes first" So, instead of saying 4lb of rice is $3.75, you should say for $3.75 I get 4lb of rice. put money first in your sentence. And use calculator like how you say it.
- For $3.75 you get 4lbs of rice.
Calculator: 3.75 ÷ 4 =
Answer $.937 per pound.
- For $7.95 you get 9lbs of rice.
Calculator: 7.95 ÷ 9 =
Answer: $.883 per pound
So, it is more economical if you buy 9lb bag.