Most people don't do complex math problems every day, but pretty much everybody has to do at least a little simple addition on a daily or near-daily basis.

Tallying the money in your wallet? Addition! Figuring out the cost of that vacation you’re planning? Addition! Painfully working out how many hours of sleep you did (or didn’t) get as your baby woke you up 7 times last night? Surprise…still addition!

I figure that since we all have to do it, we may as well learn how to do it well—by which I mean accurately and quickly. Which is precisely why we took some time last week to talk about 3 tips for adding quickly.

But turns out there are a lot more than just those three tips that you can use to help you add more quickly. So today, we’re going to talk about 2 more tips that will help turn you into a super-fast, super-accurate, and super-cool number-adder-upper extraordinaire..

How to Add Quickly (the Story So Far)

In addition to the 3 tips from last week’s show, we’ve learned another thing or 2 (or 3 or 4) about adding quickly over the life of this column. So before jumping into today’s pair of time-saving tips, let’s quickly recap everything we’ve learned so far about adding numbers quickly.

Way back in our first pair of eposides on adding quickly (which were the 8th and 9th episodes of this now 245 episode-long podcast!), we learned 2 important tips:

When adding columns of numbers, always look for pairs (or groups) of numbers that add up to 10. It’s simple to see when numbers add to 10, and adding multiple 10s together is easy - so this is a big time saver. To add quickly, don’t add from right-to-left as many of us were taught. Instead, start with the far-left column and work your way to the right. If you missed this one and aren't sure what I mean, check out the episode on this tip, and the video I made describing how to use it.

And then, last week we learned these three big tips:

Just as subvocalizing words slows you down when reading, subvocalizing numbers and operations slows you down when adding. So don’t do it. If you’re only interested in an estimated answer, don’t be afraid to round all the numbers you’re adding to whatever digit you want your answer to be accurate to before you do the addition. This will save you a lot of time and effort, and the result will be a good estimate. Look for multiple copies of the same number in any list you’re adding. If several exist, use multiplication to come up with the total for these numbers before adding this total to the rest.

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