One of the biggest challenges we face when teaching math is the big question: when am I ever going to use this again? It’s a question that many math teachers hear, as well as our instructors at Mathnasium of Parker. When students are sitting in front of a white board with a bunch of abstract numbers and equations they’re supposed to solve, the connection to math in the real world may seem far-fetched. It’s even possible for adults to think this way – how on earth did all those numbers amount to anything that has been useful. Well, there are actually two different ways we can dissect this question: one is a more literal approach and the other is a more allegorical line of thinking.

More rhetorically speaking, math is way to open lines of thinking. By learning fundamentals in math, you’re taking something and building on it, then learning the next step and then building on that and so and so forth. If you think about many careers, post-secondary education, sports or music theory related stuff, it follows the same pattern. Once you learn one concept, you use that knowledge to learn another concept and as you keep doing that, you become a master at whatever it is you’re into. So really, math is teaching you good study and brain development habits. More literally, math is used in so many forms of adult life, even if you don’t use it in your job. There are so many examples of this – too many to name here – but we do have some shortcuts for you to be able to literally use math in your everyday life to make it easier. Below are 6 life hacks where math is extremely useful.

#### 1. Converting Your Salary to Hourly

If you’re a salaried employee and you’re considering a part time job to supplement income or our of boredom with your current job, you might want to easily be able to figure out what you’re actually paid hourly to work your fulltime 40 hour a week job. All you have to do, is take your salary, drop the last three zeros from it and divide by the number two. So if you’re earning $70,000 a year, you’re being paid $35 an hour to work a 40 hour a week fulltime job.

#### 2. Percentage Calculation

Almost all of us go out to eat at some point, if not fairly regularly. You’ve then probably experienced “I hope I tipped the server enough” feeling when you haven’t pulled out your phone calculator to help you. Well, we’re here to rescue you. The quickest way to calculate percentages is to multiply numbers first and then place the decimals. Percentages are fractions and then are based on 100 with that in mind…

- Need to figure out 30% of 80? Take the first number in each one of those numbers and times them. In this case, 3 x 8 is 24. 30% of 80 is 24.
- Taking the first number in each one of those numbers multiplying them also gives you what 80% of 30 is.
- If you need to calculate the percentage of a number, such as 62 or 49, round up and down to the nearest multiple (60 and 50) to get a quick estimate.
- Lastly, for tipping, take the total bill and move the decimal point one place to the left. Then take that number and roughly double it. Say like the bill is $72.48. Move the decimal one to the left, to make it 7.248 and then roughly double this number. You come up with roughly $14 or $15 for a 20% tip.

#### 3. Asset Allocation by Age

Not everyone has a financial planner – especially if you’re far from retirement. You then might need help with asset allocation. A simple way to find out what your asset allocation according to what most financial planners would advise is to subtract your age from the number 120. The number remaining is the percentage of your portfolio that should be in stocks. Say like you’re 42. You should be keeping 78% of your holdings in stocks with the remaining 42% in fixed income products.

#### 4. The Rule of 72

If you’re interested in knowing how long it will take for your money to double at any sort of interest rate? The best and fastest way to figure out the estimated compound interest is to use the rule of 72. Just divide the number 72 by your target interest rate and you will understand the approximate number of years it will take for your money to double. So, if you were to invest in a mutual fund with an 8% return, it would take about 9 years for the funds you originally invested to double.

#### 5. Multiplying By 11

There may not be a ton of times you need to multiply by 11, but if you are ever in a predicament to multiply something by a 11, whether it is a fixed income or cost to pay something off without interest, there’s a fast trick: you leave the last and first digits in the number being multiplied by 11 alone, then you sum the rest of every pair digits next to each other. Here’s an example:

3,228 x 11 can be calculated by looking at it like (3)(3x2)(2x2)(2x8)(8) = 35,508. When the sum of a pair is greater than 10, you add the one to the next left pair. In the instance above 8x2 is 10, so the one was carried over the pair on the left (2x2) to make it five, instead of four.