Can You Pass This Basic 2-Digit Number Subtraction Test Without Using a Calculator?

EDUCATION

Robin Tyler

5 Min Quiz

Image: shutterstock

About This Quiz

93, 27, 55, 18. Or take these and subtract another set of numbers, like 93-27 or 55-20. Can you subtract those in your head? Is mental mathematics something you find simple and easy to do?

So you reckon then that you are a bit of a math wizard? Well, you're lucky - some of us need the calculator, even for basic two-digit number subtraction.

Remember when our teachers back in school emphasized the importance of not always relying on your calculator to do the math for you? That by doing so, you would get lazy? That you should develop your own system to help you subtract numbers easily?

I am sure you have a system that works for you in that regard. 

There are many ways to subtract numbers in our heads; it's about finding a system that works for you (and if you take this test, we will show a method that we use).

So what can you expect from this test?  Thirty-five questions of basic two-digit number subtraction. If you are good at this sort of thing, you really will fly through this test in no time at all. Can you get 100%, though? Sometimes numbers can trick us! 

Let's see how you fare! Good luck! 

99-77=___?

Simple. Break it down like this. 9-7 is 2 and 9-7 is 2, so 22.

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Subtract 41 from 88. How much are you left with?

88 minus 40 would leave you with 48, then you still need to subtract the 1, so the answer is 47. You got it, right?

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If you have 62 bananas and your friend eats 44 of them, how much do you have left?

Well, other than the fact that you might need to rush your friend to the hospital, you would only have 18 bananas left. We got to the answer by taking 62 and subtracting 40 to get to 22, and then taking off the remaining 4 to get to 18.

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Take 57 and subtract 18 from that. What do you have left?

57 -17 would give you 40, so take off the extra 1 for 39! Tricky strategy helps.

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87-53=___?

8 minus 5 is 3 and 7 minus 3 is 4. That leaves you with 34 as your answer. Did you use the same method to work it out as we did?

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44 minus 21 leaves you with what?

4-2 is 2 and 4-1 is 3, so that makes 23! Easy, right?

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87-41=___?

Another easy one, it's an even number and its 46! How? 8 minus 4 is 4 and 7 minus 1 is 6, leaving 46.

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Take 71 and subtract 32 from it. What do you have?

Not too difficult. The answer is 39. How? Well 70 minus 30 would give you 40. Add 1 for the 71 which leaves you with 41 and then subtract 2 to round the 30 up to the original 32. Does that make sense?

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If you have 33 apples taken away from your stash of 88 apples, how many apples do you have left?

8-3 is 5 and 8-3 is 5 again, leaving you with 55. Super simple.

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91-64=___?

This is a fairly simply subtraction problem. Again take 90 minus 60, that leaves you with 30. Add the 1 left over from the 91 and subtract the 4 left over from the 64. That leave you with 27.

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Subtract 55 from 92 and what do you have?

If you had 90 and took away 55, you would have 35. That's easy to work out, but now you still have the extra two, as the number was 92. So you need to add that to 35 and you have 37.

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Take 64, then subtract 11 from it. What do you have left?

Too easy. No way you didn't get 53 for your answer. Our brains just automatically can see answers like that without even needing to think about it. If you got it wrong, don't tell anyone!

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11-12=___?

It's negative number, expect a few more. The answer is -1.

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Here's another! What is 77-99?

Well, 99 minus 77 would be 22, so 77 minus 99 is simply -22. Do you see how easy it is, actually?

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75-24=___?

Easy if you do it this way. 7-2 is 5 and 5-4 is 1, so the answer is 51.

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65-28=___?

So simple. Just round up again. So 65 minus 30 would be 35, right? Now add the extra 2 from the 28 and you have our answer, 37.

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If you have 77 pebbles and you lose 49, how many do you have left?

A lot less pebbles. Actually, you would only have 28 left. There are a few ways to get to this answer, but we rounded up the 49 to 50. So 77 minus 50 is 27 but then you still have to add 1 (it was 49 not 50, remember). So that leave you with 28.

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Subtract 22 from 10, please?

Another negative answer but easy to work out. it is -12.

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If you take 66 from 98, what do you have left?

9-6 is 3 and 8-6 is 2, and therefore the answer is 32. It really is a simple way of doing subtraction. If you put it into logical steps like this, you can work it out in seconds.

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79-21=___?

The answer is 58. 80 minus 20 would be 60, but now you have to remove the two extra numbers, as the originals were 79 and 21, so that makes the answer 58.

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63-39=___?

Ok, we had 63, took off 40. That left 23, but you still need to add 1 because the second number was 39, not 40. That leaves the answer at 24. Crazy that we are adding when we subtracting. This is just one of the ways you can do it.

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99-45=___?

9-4 is 5 and 9-5 is 4, so the answer is 54. I love it when all the numbers work out so easily. You got that one, right?

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If you take 25 from 75, what are you left with?

We got to the answer of 50 by taking 7 minus 2 and 5 minus 5, which leaves you with 50. You got that right?

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You have 88 candies and lose 27. What have you got left?

A hole in your pocket? No! it's 61. To get there, we calculated 8 minus 2 and 8 minus 7. That gives you 61! Hope you find your candies!

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45-32=___?

Very straightforward this one. Your brain should have flashed you the number straight away. It's 13.

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83 minus 33 gives you how much?

So easy. 80 minus 50 give you 30. The 3's cancel each other out. So 50 is your answer.

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Subtracting 66 from 33 gives you how much?

66 minus 33 is easy. It's 33. but this is going to be a negative number. That's fine, as 33 minus 66 still give you 33, its just negative 33.

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54-24=___?

Ok, it's easy to see when subtracting, the 4's will cancel each other out. So that means its 50 - 20 in fact, and that's easy to work out. It is 30.

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If you had 69 apples and your friend ate 24, how many would you have left?

6-2 is 4 and 9-4 is 5, therefore 45 apples are left. Your friend needs some help!

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If you removed 47 from 91, how much would you have?

The answer is 44. We got there by starting with 90 and taking away 47 to give us 43. Add the 1 left over for rounding down to 90 and you have 44. You knew that though, didn't you?

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91-53=___?

An even number, the answer is 38. And we got there by starting with 90, removing 50. That leaves 40. Add 1, because the original number was 91 then remove 3 because the other original number was 53.

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80-41=___?

The answer is 39. No explanation necessary, really. 80 minus 40 would be 40. Subtract the extra 1 from rounding down the 41.

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Subtract 96 from 10. What do you have?

Into the negatives, but easy to work out because of the 10. A less round figure would be a little more challenge. The answer is -86, by the way.

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If you lost 19 of your 45 marbles, how many would you have left?

Losing your marbles... I feel like i might be after all this math! 45 - 20 would bet 25, but add the 1 for rounding up. And the answer is 26.

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45-45=___?

The easiest question today, right? That's a zero!

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