7 Cool Math Tricks That’ll Help You Solve Any Question in Seconds
Math might be a nightmare for most people, yet it can be a very entertaining world on its own when you know certain tricks. 5-Minute Crafts rounded up essential math tips and a bonus for you. Even if you think the numbers aren’t your cup of tea, you may end up liking it shortly.
1. Trick for multiplying by 9.
Let’s find the answer to 9 X 8 using our fingers to see how it works.
Step 1: Hold your hands out with palms facing up. Then, enumerate each of your 10 fingers, starting from 1 to 10 and moving from your left to your right thumb.
Step 2: Bend down the finger you want to multiply by 9; in our case, it’s the 8th finger — the middle finger on your left hand.
Step 3: Start counting your fingers from the left to the right until the curled one, then multiply it by 10 (tens) — in this case, you get 7 X 10 = 70. Next, count the fingers from the bent finger onwards, and multiply it by 1 (ones). In this case, you get 2. Adding the results together, the answer is 72.
Here is an exercise for you to test out this trick.
2. Multiplying a number by 7.
Step 1: Let’s find the answer to 7 X 8. Hold your hands with palms facing you, and make your fingers face each other. Enumerate your fingers from 6 to 10, ensuring your pinkies are 6, your ring fingers are 7, and the rest goes on in ascending order until your thumbs represent 10.
❗Remember that this method works for 6, 7, 8, and 9 multiplications but doesn’t work for 6 X 6.
Step 2: Remember that your left fingers represent the number on the left side of the problem (left side of the = sign of the question), while your right fingers are for the numbers on the right side. Line them up so that your left ring finger (7) touches your right middle finger (8).
Step 3: When multiplying the top fingers on your left hand by the top fingers on your right hand, you get 3 X 2 = 6. You’ve found your final answer’s second number (ones or units). Now, you have 5 fingers beneath them representing the 10s (tens). Multiply 5 by 10, and sum it up with the previously found number. The answer is 50 + 6 = 56!
3. Multiply any number by 3.
You can apply this method when multiplying by 4, too. All you need to do is assign numbers to each of your fingers. Let’s find the answer to 3 X 4!
Step 1: Spread out one of your hands and assign 3 numbers to each of your fingers. Your pinky finger will have 1, 2, 3, while your ring finger follows it up with 4, 5, and 6, etc. Repeat until you assign 13, 14, and 15 to your thumb.
❗You can start assigning numbers the other way around, from the thumb, not the pinky finger, too.
Step 2: Now that we’re calculating 3 X 4, hold up only 4 fingers, and close the rest.
Step 3: Finally, count all the numbers on 4 fingers — the answer is 12.
4. Find the perfect squares.
In math, an odd number is a number that leaves 1 as the remainder when divided by 2, such as 1, 3, 5, 7, etc. Surprisingly, when you sum the consecutive odd numbers (starting with 1), you get a perfect square number. In other words, doing the math, you get a natural number that is the square of another natural number.
5. Multiply any number by 999.
If it’s a single digit you are multiplying by, such as 6 X 999, follow this trick:
- In 999, we have three 9s. Take one of them and multiply it by six, 6 X 9 = 54. Write down 5 and 4, keeping a distance within.
- We still have two 9s left, and we write those two 9s between 5 and 4. So, the answer is 5994.
If the number you’re multiplying by has 3 digits, for example, 255 X 999, then do the following:
- First, subtract 1 from 255, and you get 254.
- Next, take the 9 at the most left, closest to the 255. Then, subtract 2. You get 9 - 2 = 7
- Repeat a similar path for the rest of the 9s. Take the middle 9 and subtract 5; it’s 9 — 5 = 4,
- Finally, take the 9 at the right end, subtract 4, and find 9 - 4 = 5.
The answer is 254745.
6. Use the butterfly method.
The butterfly method, really, makes adding and subtracting fractions a piece of cake. Let’s find the answer to 5/7 + 2/5 =?
Step 1: Draw enclosed ovals on both sides of the fractions, like a butterfly. Then, multiply the numbers inside each wing, and write down the values. For example, you get 5 X 5 = 25 and 7 X 2 = 14.
Step 2: Add the results you obtained from “Step 1” and get 25 + 14 = 39. Write it on the top right of the fraction (numerator).
Step 3: Now, multiply the denominators seen at the bottom of the fractions. Write down the product on the bottom part of the fraction (denominator), which is 5 X 7 = 35.
The answer is 39/35.
7. Subtract any number from 1000 easily.
Let’s find the answer to 1,000 — 556. First, subtract every number from 9, except the last one, because you need to subtract it from 10.
- 9 — 5 = 4
- 9 — 5 = 4
- 10 — 6 = 4, the answer is 444.