Most people assume that once they’ve got a degree tucked away, they’ve mastered the basics for life, but some of the maths problems from a few decades ago might give you a proper reality check.
We’ve become so used to having a calculator in our pockets that the mental muscles needed for old-school arithmetic have probably gone a bit soft. It’s funny how a question meant for a schoolkid in the fifties can make a modern graduate break into a cold sweat. If you can actually work these out without reaching for your phone, it’s a sign that you’ve held onto a level of logic and grit that’s becoming pretty rare. These problems aren’t just about numbers; they’re about seeing if you can still think on your feet when the tech is stripped away.
What’s 144 ÷ 12 without a calculator?
Simple division that everyone used to do in their heads, but most of us reach for our phones now. This was the kind of question you’d get thrown at you during mental maths sessions, and if you couldn’t answer within a few seconds, you’d feel the pressure mounting.
The answer’s 12, but did you work it out or just know your times tables? Either way counts, really. The point is that this stuff used to be automatic, and now we’ve all got so dependent on technology that even basic division feels like proper work. It’s not about being rubbish at maths. It’s about how our brains have shifted what they prioritise.
Convert 3/8 to a decimal.
Fractions were drilled into us back then, and converting them to decimals was something you just had to know how to do. You’d divide the top number by the bottom number, so 3 divided by 8 gives you 0.375. Dead simple when you remember the method, but if you’ve not done it in years, your brain probably stalled for a moment.
We used to have to memorise common conversions too, like knowing that 1/4 is 0.25 or 1/2 is 0.5. Now we just Google it or let the calculator handle the conversion. There’s nothing wrong with that, but it does mean we’ve lost that instant recall that used to separate the quick thinkers from everyone else.
What’s 15% of 80?
Percentages come up all the time in real life, but most people still panic when they have to work them out without help. The old school method was to find 10% first (which is 8), then find 5% by halving that (which gives you 4), then add them together to get 12.
It’s a brilliant little trick that works for any percentage calculation, but these days, we’re more likely to reach for our phones than do the mental arithmetic. Shop sales used to be a proper workout for your brain. Now the till does it for you, and you just nod along without checking if it’s right. The skill’s still useful, though, especially when you’re trying to work out tips or split bills.
Solve for x: 3x + 7 = 22.
Algebra made everyone groan in school, but this is one of the simpler equations. You subtract 7 from both sides to get 3x = 15, then divide both sides by 3 to get x = 5. The method was all about balancing both sides of the equation, and once you got the hang of it, you could solve these in your sleep.
The problem is that unless you’ve used algebra in your job or kept up with it somehow, your brain’s probably forgotten the rules. You might remember that x is meant to be on its own, but the actual steps to get there feel fuzzy. That’s the thing with maths—it disappears fast if you don’t use it.
What’s the area of a triangle with a base of 10 cm and a height of 6 cm?
The formula’s half the base times the height, so you’d do 10 times 6 to get 60, then divide by 2 to get 30 square centimetres. Easy enough when you remember the formula, but most people have completely forgotten it. We learned loads of these formulas by heart—triangles, circles, rectangles, trapeziums—and we had to apply them in exam conditions without any help.
These days, you can just look up any formula you need within seconds, so there’s no real reason to memorise them. But there’s something satisfying about still knowing them off the top of your head, like you’ve held onto a piece of your education that actually stuck.
Work out 7 x 8.
Times tables were the foundation of everything, and if you didn’t know them, you’d struggle with pretty much all maths going forward. This one’s 56, and you either knew it instantly or you didn’t. Teachers used to test us with rapid-fire questions, and you’d feel your heart race when it was your turn.
The embarrassment of getting one wrong in front of the class was enough motivation to learn them properly. Now kids use apps and songs to memorise them, which probably works just as well, but there’s something about the old-fashioned drilling that made them stick forever. Even people who claim they’re terrible at maths can usually rattle off their times tables without much trouble.
What’s 2 to the power of 5?
Powers and indices were another thing that got hammered into us, and this one means 2 multiplied by itself five times. So that’s 2 x 2 x 2 x 2 x 2, which equals 32. It’s one of those calculations that feels harder than it is because the concept of powers can seem abstract. But once you get the hang of it, it’s just repeated multiplication.
The tricky bit was remembering the rules, like anything to the power of 0 equals 1, or how to handle negative powers. Most of that’s gone now unless you’ve kept up with it, and honestly, there aren’t many situations in everyday life where you need to know what 2 to the power of 5 is.
Convert 0.6 to a fraction.
Going the other way—decimal to fraction—was just as important as the reverse. This one’s 6/10, which simplifies down to 3/5 when you divide both numbers by 2. The key was knowing how to simplify fractions by finding common factors, which was another skill that got drilled into us until it became automatic.
These days, most people don’t bother simplifying fractions in their heads. We just leave them as they are or let technology sort it out. But being able to switch between decimals and fractions used to be essential, especially for anything involving measurements or recipes. It’s one of those skills that feels pointless until you actually need it.
What’s the perimeter of a rectangle with sides of 12 cm and 8 cm?
Perimeter just means adding up all the sides, so you’d do 12 + 12 + 8 + 8, which gives you 40 cm. Alternatively, you could do 2 x (12 + 8) to get the same answer. It’s straightforward enough, but again, it’s one of those things that slips away if you’re not using it.
We learned perimeter and area at the same time, and the two got confused constantly. Perimeter’s the distance around the outside, area’s the space inside. Simple distinction, but it tripped up loads of people in exams. The real test was whether you could remember which formula went with which shape and apply it correctly under pressure.
Solve 48 ÷ 6 + 3 x 2.
Order of operations was a big deal—BODMAS or BIDMAS, depending on which version you learned. Brackets, Orders (or Indices), Division, Multiplication, Addition, Subtraction. You have to do division and multiplication before addition, so you’d work out 48 ÷ 6 to get 8, then 3 x 2 to get 6, then add those together to get 14.
Miss the order and you’ll get it completely wrong, which is why this rule got drilled into us so hard. It’s one of the few maths rules that actually comes up fairly regularly, especially if you’re trying to work out calculations in spreadsheets or programming. Getting it wrong can throw off entire formulas.
What’s 25% of 200?
Another percentage question, but this one’s easier because 25% is just a quarter. A quarter of 200 is 50, so that’s your answer. This was one of the shortcuts we learned—certain percentages had quick tricks. 50% is half, 25% is a quarter, 10% is moving the decimal point.
Knowing these made percentage calculations much faster, and they’re genuinely useful in everyday life. Whether you’re working out discounts, tips, or tax, being able to calculate percentages quickly saves time and stops you getting ripped off. It’s probably the most practical maths skill from school that still gets regular use.
Convert 2.5 hours to minutes.
Time conversions were another staple, and this one’s straightforward. There are 60 minutes in an hour, so 2 hours is 120 minutes, and the extra 0.5 hours is 30 minutes. Add them together and you get 150 minutes. We did loads of these conversions—hours to minutes, minutes to seconds, days to hours.
They’re actually really useful for working out journey times, cooking durations, or how long you’ve got left on a task. Digital clocks have made us lazy about thinking in different time units, but it’s still a skill worth having. Plus, it stops you making embarrassing mistakes like thinking a 90-minute film is only an hour long.
What’s the square root of 64?
Square roots were the opposite of squaring numbers, and this one’s 8 because 8 x 8 = 64. We had to memorise the most common square roots—4, 9, 16, 25, 36, 49, 64, 81, 100—because they came up constantly in algebra and geometry. Anything beyond that and you’d need a calculator or a table of square roots.
These days, nobody memorises them anymore. We just punch the number into a calculator and move on. But knowing the common ones by heart used to be a mark of someone who was decent at maths. It’s one of those things that made you feel clever when you could rattle them off without thinking.
Work out 9 x 12.
This sits just outside the standard times tables grid that went up to 10 x 10, so it used to catch people out. The answer’s 108, and you might’ve worked it out by doing 9 x 10 plus 9 x 2, or by knowing your extended times tables. Either way, it required a bit more thought than the basics.
These edge cases were where you could see who really understood multiplication versus who’d just memorised patterns. Being able to extend your times tables knowledge to bigger numbers was a sign you’d properly grasped how multiplication worked. Now we’d all just reach for our phones without a second thought.
What’s 3/4 of 60?
Finding fractions of amounts was another core skill. You’d work out 1/4 first by dividing 60 by 4 to get 15, then multiply by 3 to get 45. Or you could do 3 x 60 divided by 4, which gives you the same answer. The method didn’t really matter, as long as you got there.
These questions came up everywhere—in recipes, in measurements, in money calculations. Being able to work them out without a calculator used to be standard, and honestly, it’s still handy now. If you can do this stuff in your head, you’re ahead of most people, and that’s saying something about how much we’ve let these skills slide.
