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How can you multiply and divide in your head without using a calculator?
Wiki User
∙ 13y ago
For multiplication, just break it down into small bits in pieces, especially easy numbers like 2, 3, 5, 10, and 12. And then just multiply those instead. If needed, you can also use this: ac + bc = c(a+b)
For example, 12 * 320 = 12 * 4 * 8 * 10, which is 48 * 8 * 10. Okay now, you have to multiply 48 and 8! Then you break that down. 48 * 8 = (40 * 8) + (8 * 8).
That is 320 + 64, or 384. Then multiply that by 10. You get 3840! It may take some practice, but when you succeed, you will be amazing!
I have to say, pretty much the same for division.
Wiki User
∙ 13y ago
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How do you convert one eighth into a decimal without using a calculator?
Divide the numerator by the denominator
How do you divide circumference by pi?
How about using a calculator!
How do you convert yd to meters using a calculator?
Multiply by 0.9144
How do you convert the fraction seventeen over twenty into a percent without using a calculator?
Multiply both numbers by five- to get the fraction 85/100... which is 85%
How do you get a product from two numbers?
You multiply the number together - using a calculator if needed.
How do you convert one eighth into a decimal without using a calculator?
Divide the numerator by the denominator
What is the formula to convert fraction to percantage?
Multiply the numerator of the fraction by 100 and then divide (using long division if needed or a calculator) by the denominator.
How do you explain how to find percent equivalent of 17 out of 20 without using a calculator?
% rate:1. Divide 17 by 20.2. Multiply the quotient by 100%= (17 ÷ 20) x 100%= 0.85 x 100%= 85%
How do you divide 0.0038 by 0.0689?
by using a calculator
How do you divide circumference by pi?
How about using a calculator!
How do you multiply any size number by 4 without using a calculator?
with your brain... Or the old-fashioned way -by counting it out on your fingers.
How do you multiply a fraction by a whole number without using a model or repeated addition?
Multiply the whole number times the numerator. Divide the product by the denominator.
Explain one way to find the equivalent percent for 3 out of 5 without using a calculator?
you divide 3 by 5 :P
How do you convert yd to meters using a calculator?
Multiply by 0.9144
How do you do percent of a number on a calculator?
Two choices: -- Multiply (the number) x (the percent using the percent % key). -- Multiply (the number) x (the percent), then divide the answer by 100. Either way, the claculator displays that many percent of that number.
How do you convert the fraction seventeen over twenty into a percent without using a calculator?
Multiply both numbers by five- to get the fraction 85/100... which is 85%
Write the fraction as an equivalent percent?
To write a fraction as a percent, simply divide the numerator by the denominator (in your head, with a computer or calculator, or by hand using long division). Then simply multiply the answer by 100. Example: Write the fraction 3/8 as a percent. Answer: If we divide 3 by 8, we get 0.375. Multiply that by 100 to get 37.5%.
