Content

• Steps

There are times when you realize you have to solve a problem without a computer. Even if you are good at math, arithmetic can be an extremely difficult task. To solve a mental math problem, you need a completely new set of strategies and methods that are different from what you learned in school.Fortunately, if you learn the basics of the rules and use mental math strategies, you can improve your skills in solving complex math problems in your mind.

Steps

Method 1 of 3: Use arithmetic tips

1. 

   Visualize the equation in your mind. The first step to solving a mental math problem is to visualize the problem. Visualize the numbers and equations in your head. As you solve problems, imagine the new numbers that you are working with. By repeating these numbers in your head, speaking out loud or in a whisper, you may remember the more important numbers in the equation.

2. 

   
   
   Add and subtract from left to right. You may have been taught to add and subtract from right to left, but doing so is actually more difficult with arithmetic. Instead, calculate the numbers to the left first, then subtract or add the numbers on the right side. The number on the left will form the number to the left of the answer and the number on the right will be the second digit of the answer.
   • For example, to do the calculation 52 + 43, you could calculate 5 + 4 = 9 and 2 + 3 = 5 to get a total of 95.
   • If doing the 93-22 calculation, calculate 9-2 = 7 then 3-2 = 1 to get a difference of 71.
   • If you remember to add, add to the first number of the answer. For example, when doing 99 + 87, you can add 9 + 8 first to get 17, then add 9 + 7 to get 16. You know you have to remember 1, so the first number the first would become 18, and the result would be 186.

3. 

   
   
   Handles common zeros when adding or subtracting. When doing addition, you can find common zeros in the equation and remove them to make solving the equation easier. For example, with the 120-70 calculation, you could remove the zeros to get 12-7 = 5, and then return 0 back to get the answer of 50.
   • Another example is the calculation 300 + 200, you can remove the general zeros to get 3 + 2 = 5, then return the zeros to get the answer of 500.

4. 

   
   
   Simplify and then return all zeros when multiplying. By multiplying numbers together, you can simplify numbers with leading zeroes. For example, if you have a calculation of 3.000x50, you can shorten it to 3x5 = 15, and then return all zeros after the product you just got to get a answer of 150,000.
   • Another example is the 70x60 calculation, you could do the calculation 7x6 = 42, and then return all the zeros to get the answer of 4,200.

5. 

   Round the numbers up, then subtract the added portion. You can round up to the number up, then subtract the added value to make it easier to solve complex problems with values ​​greater than 100. For example, if you have to do the calculation 596 + 380, you can add 4 to 596 to get the equation 600 + 380 = 980, which makes it easier to imagine. Next, you need to subtract 4 out of 980 to get 976 for 596 + 380.
   • As another example, if you need to calculate 558 + 305, round 558 to 560 to get the equation 560 + 305 = 865. Then you would have to subtract 2 from 865 to get the final answer. 863.

6. 

   Simplify complex numbers when doing multiplication. You don't have to do the exact calculation in place. Complex and odd numbers can make the problem more difficult. For example, if you want to calculate 12x36, you can simplify the numbers to make the math easier. 12 can be reduced to 10 to get 10x36, which is 360. Then you need to take the uncut, which is 2, multiply by 36 to get 72. Finally, you need to calculate 360 ​​+ 72 to get the answer. 432. This could be easier than calculating the long-line multiplication problem.

7. 

   Reduce percentage numbers to even numbers. Divide percentages into smaller chunks if possible. For example, if you need to calculate 15% of 40, you can calculate 10% of 40 to get the figure 4. Then, since 5% is half of 10%, you can calculate 5% of 40 as 2. Calculate 4 + 2 = 6. Thus, 15% of 40 is 6.

8. 

   Use estimation with calculations that do not need to be very precise. Estimating answers is often much easier than calculating accurately. Try rounding up complex numbers and then solving the equation. In cases where the exact answer is not required or the time is limited, use an estimate to get an approximate answer.
   • For example, if you have to calculate 7.07 + 8.95 + 10.09, you can round to the nearest number and estimate the approximate answer to be 26.

9. 

   Associate the value of money and use it to solve the equation. Since a dollar consists of 100 cents, you can easily use this knowledge to solve mathematical equations. For example, you may not have immediately come up with how much 100-25 will equal how much, but perhaps you know how much money you have left if you spend all the 25 cents out of four 25 cents. If you can, relate the numbers in the equation to money values ​​in the calculation. advertisement

Method 2 of 3: Learn and practice to improve skills

1. 

   Memorize the multiplication tables. By memorizing the multiplication table, you will immediately have the answer to simple multiplication operations. This will help you improve the speed at which small parts of a more complex problem are calculated. If you are still confused with the multiplication table, study until you know all the multiplication operations in it.

2. 

   Memorize the square of the first 20 numbers. The squared table will show the result of the numbers 1 through 20 multiplied by itself. The square table will allow you to solve simple quadratic equations using mental arithmetic. You can also use squared numbers to calculate in more complex multiplication operations.
   • For example, if you have to calculate 18x19, you can calculate 19², then subtract 19 to get the answer.

3. 

   Use school cards. If you have trouble learning your multiplication table or division, memory cards are a great way to memorize common math problems. Determine where you usually run into trouble, and write that equation on your card. Write your answers on the back of the card. Ask another person to practice with the memory cards so you can use your memory to solve common math equations.

4. 

   Daily mental math. Practicing two or three complex math equations every day will help you maintain your mental sharpness and dramatically improve your mental math skills. Try to do mental math in a variety of situations to improve your skills. After a month, you will find it easier to do mental arithmetic.

5. 

   Do mental math problems online. There are apps and websites to help you hone your mental math skills. Browse the top rated apps and websites online and use their online tools to practice common mental math equations.
   • You can find popular quizzes on sites like http://preplounge.com and http://flexmath.ck12.org/.
   • Popular mental math applications include Elevate, Luminosity, and Mathemagics.
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Method 3 of 3: Practice mental arithmetic while shopping

1. 

   Practice addition and subtraction to calculate the amount on the bill. Remember the prices of all items purchased at the supermarket before going to the checkout counter. Add the prices of each item together and remember the total cost. When you receive your bill, compare the calculated number with the actual value of your purchase.
   • For example, if a cereal box for breakfast costs 51,000VND and shower gel for 249,000VND, the total price you will pay would be 300,000VND.

2. 

   Do the multiplication to calculate the cost of buying gasoline. Wait until the fuel tank is nearly exhausted, then multiply the fuel price by the capacity of the tank. For example, if you have a 4-liter fuel tank and the gas price is 19,000VND / liter, do the calculation 4x19,000 = 76,000VND. You can also cover the price on the gas pump while looking at the gallons of gas and figure out the total.
   • You can use multiplication to figure out how much to pay when buying items with quantity more than one.
     • For example, if you buy 4 candy bars that cost 5,000VND per bar, you will have 4x5,000 = 20,000VND.

3. 

   Use the discount and discount numbers to practice calculating percentages. Round the price of the product to the nearest even amount and calculate the percentage of the selling price. For example, if an item with a 7% discount costs 98,000VND, you can round up to 100,000VND. So 7% of 100,000 is 7,000VND, equivalent to the money you save.
   • Ten percent of 98,000VND is exactly 9,800VND.
   • If you buy a water bottle that costs $ 5 and gets a 25% discount, your savings will be $ 1.25.

4. 

   Calculate division to divide money in the bill. If more than one person pays the same bill, you can divide the amount on the bill by the number of people to see how much each person should pay.For example, if your electricity bill is $ 125.36 and you have 3 more people sharing a room, the $ 125.36 will be divided by 4 to get $ 31.34 per person.
   • If you want to divide the equation for easy calculation, divide the dollar first, then the cent.
   • Take $ 100 out of $ 125 to make it easier to divide by 4. You will have $ 100/4 = 25. Then you will divide $ 25 by 4 to get the balance. Add $ 6 to $ 25 to get the final number $ 31.
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