Can You Pass This Basic 3-Digit Number Addition Test Without Using a Calculator?

By: Zoe Samuel
Estimated Completion Time
1 min
Can You Pass This Basic 3-Digit Number Addition Test Without Using a Calculator?
Image: Shutterstock

About This Quiz

Remember how we all used to say, "But Miss Mathteacher, we can just use a calculator?" and she would put us in our places by saying, "You won't always have one with you when you're out and about, will you?" Then along came the smartphone, with its dozens of apps, the least of which can calculate far more with a few taps than even Stephen Hawking could do in his head. Oh, how we laughed at Miss Mathteacher! What a fool she was, to be overtaken by technology - and so quickly!

The truth, though, is that she's still right. Being able to crunch numbers in your head is still important. It's partly that you should be able to detect when numbers just feel off; for example, when a bill seems too high or when the expenses on your spreadsheet are adding up funny. It helps you to spot anomalies like an extra item where it doesn't belong or a misplaced bracket or equals sign that's causing the whole spreadsheet to go kerblooey. It's also just plain handy for when you genuinely don't have a calculator; after all, sometimes your phone dies. More importantly, being able to run figures in your head is a baseline life skill, like being able to cook. So many other skills rest on it that letting it atrophy is actually dangerous for your ability to think clearly, and not just about math; it's also about your ability to deduce a conclusion rationally from a premise. It makes you harder to trick, and just plain smarter.

That's why, doubtless, you've kept that part of your brain spick and span ... and now's your chance to prove it!

What is 666 + 583?
1240
1249
1230
1250
Correct Answer
Wrong Answer

The right answer is 1249!

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What is 2.02 + 2.12?
2.22
4.14
2.00
2.21
Correct Answer
Wrong Answer

That's right, if you have a 2 and another 2, the answer has to be over 4. You don't even need to look after the decimals.

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What is 243 + 838?
900
1099
999
1081
Correct Answer
Wrong Answer

The right answer is 1081.

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What is 644 + 644?
1200
1150
1080
1288
Correct Answer
Wrong Answer

The right answer is 1288!

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What is 19.3 + 833?
852.3
834
845
852
Correct Answer
Wrong Answer

Oh, those cheeky decimals! Here they are working together with an integer to mess with your head.

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What is 334 + 924?
777
737
1258
1499
Correct Answer
Wrong Answer

The right answer is 1258!

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What is 833 + 226?
942
958
1059
998
Correct Answer
Wrong Answer

The right answer is 1059!

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What is 728 + 147?
122
797
875
804
Correct Answer
Wrong Answer

An odd and an even? That's an odd.

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What is 737 + 222?
959
550
990
840
Correct Answer
Wrong Answer

The right answer is 959!

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What is 333 + 232?
799
565
787
698
Correct Answer
Wrong Answer

The right answer is 565!

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What is 727 + 737?
1460
1400
1500
1464
Correct Answer
Wrong Answer

The right answer is 1464!

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What is 484 + 0.01?
494
484.01
474
484
Correct Answer
Wrong Answer

We're down into the hundredths. Technically, this is still a triple-digit number, it's just much smaller than some.

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What is 833 + 484?
1316
1318
1320
1317
Correct Answer
Wrong Answer

An odd and an even number always make an odd number.

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What is 501 + 499?
900
1000
600
1100
Correct Answer
Wrong Answer

The right answer is 1000 flat.

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What is 273 + 964?
1022
1237
988
1050
Correct Answer
Wrong Answer

The right answer is 1237!

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What is 2.33 + 10.1?
11.43
12.43
15.43
20.43
Correct Answer
Wrong Answer

One of these is to one decimal place, the other to two. That's confusing unless you are on the ball.

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What is 172 + 182?
273
354
220
351
Correct Answer
Wrong Answer

The right answer is 354.

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What is 100 + 1.00?
200
101
500
1000
Correct Answer
Wrong Answer

We fooled you with the decimal ... or did we? That's right, we're getting into decimals now.

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What is 10.4 + 3.22?
130.2
132.6
13.62
132.6
Correct Answer
Wrong Answer

Don't miss those decimals. They'll get the best of you!

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What is 353 + 111?
464
564
664
764
Correct Answer
Wrong Answer

The right answer is 464.

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What is -284 + 101?
-183
283
-384
-484
Correct Answer
Wrong Answer

Even though some progress was made back towards 0, it's still negative!

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What is 836 + 183?
1019
1001
999
1011
Correct Answer
Wrong Answer

The right answer is 1019!

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What is 9.24 + 82.3?
101.1
82.34
91.54
76.01
Correct Answer
Wrong Answer

This looks like it should end in an odd number but actually it doesn't have to. That's because .3 is really .30.

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What is 743 + 199?
200
942
1042
943
Correct Answer
Wrong Answer

The right answer is 942.

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What is 5.43 + 300?
503.40
305.43
350.40
403.55
Correct Answer
Wrong Answer

It's an integer plus a decimal, so of course it can't be a round number. You just have to think of the integer as having .00 after it.

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What is 721 + 279?
1200
1150
1000
950
Correct Answer
Wrong Answer

It's 1000 again.

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What is 3.12 + 1.09?
40.2
42.1
4.21
40.1
Correct Answer
Wrong Answer

They're little numbers so the answer is little!

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What is 4.53 + 9.99?
14.52
1.52
99.43
103.4
Correct Answer
Wrong Answer

More tricky decimals! But here it's still a fairly simple business to add them up.

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What is 294 + 6.00?
310
299.5
300
301.05
Correct Answer
Wrong Answer

300 is a round number and anything ending .00 is a round number.

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What is 373 + 211?
584
699
564
400
Correct Answer
Wrong Answer

The right answer is 584!

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What is 991+101?
1092
1022
1011
1024
Correct Answer
Wrong Answer

The right answer is 1092.

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What is -100 + -101?
-201
200
201
2001
Correct Answer
Wrong Answer

Did you notice the negative signs? If you did, you'll have gotten the right answer.

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What is -712 + -274?
548
-986
-548
-106
Correct Answer
Wrong Answer

Two negatives, so you just go all the way negative!

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What is -342 + 733?
1075
733
391
-391
Correct Answer
Wrong Answer

There's one positive and one negative number here, so you just deduct the negative from the positive.

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What is -377 + -223?
1000
600
-154
-600
Correct Answer
Wrong Answer

It's two negative numbers here. So you just add them together and put a minus sign in front of it!

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You Got:
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