Q&A for How to Multiply

First, temporarily remove the decimal points and multiply 2279 by 29. Then, note that there are a total of seven decimal places to the right of the decimal points in the two numbers. The decimal point in the final product is placed by counting seven spaces from the right, so that there are seven decimal places to the right of the final decimal point.

You do the same thing as method 2 and ignore the decimal until the end and count the numbers that are behind the decimal. In your answer count from right to left and place the decimal, for example: 0.3x0.4=.12 -- in the beginning 2 numbers all together were behind the decimal and in the end 2 numbers were behind the decimal.

If one number is 0 then the product is 0. For example: 2 x 0 = 0 because two groups of zero means that 0+0=0.

Let 814 be the top number if possible - it's easier that way. If 8 has to be the top number, you'll just have to multiply the 8 three times (by 4, 1, and 8), making sure each partial product is placed in the correct columns. Essentially you're just doing the same process backwards.

Method 1 is meant for simpler problems. If you wanted to use it, it would work the same way as the example - you'd have to make 23 groups of 32 and add them all up (32 + 32 + 32 + .... + 32). You should use Method 2 for this one.

Multiply the whole number by the numerator of the fraction, and leave the denominator unchanged. Then convert the answer to a mixed number, if needed. For multiplying two fractions together, see How to Multiply Fractions .

Multiply the numerator by the whole number. Leave the denominator unchanged. Reduce the final fraction if possible. The final answer will be a mixed number if the final numerator is larger than the denominator. For example, to multiply 5 by 8/10, you would multiple 5 by 8 to get 40, which would then become 40/10, which is reduced to 4.

It doesn't matter which number is on top: you do it the same either way. Ignore the decimal point until the very end. Multiply 365 by 82. Then you position the decimal point one place to the left of the right end of the product (because there is a total of one decimal place in the original numbers being multiplied).

Use the technique shown in Method 2 above with one extra (but identical) step.

Of course, but the whole point of studying a subject is to understand the principles and operations involved (and to avoid being helpless should a calculator be unavailable).

If you're careful, any method will be accurate. The box method is just a way to show more clearly what is happening when we multiply. It, too, could be subject to mistakes if we're not careful.

You can use any method for 24 x 49. Long multiplication might be the best option.

Move the decimal point in the first number two places to the right. (100 has two zeros in it, so you move the decimal point two places.) The answer is 314.

First multiply the multiplicand by the ones digit of the multiplier. Write the partial product directly below the multiplier. Next multiply the multiplicand by the tens digit of the multiplier, and write that partial product below the first partial product offset to the left one column. Finally multiply the multiplicand by the hundreds digit of the multiplier, and write that partial product below the second partial product offset to the left one column. Then add up each column (carrying when necessary) to find the final product.

(4)(8) = (4)(5 + 3) = (20) + (12) = 32.

The same process with any digit, but it's recommended to use a calculator to solve something like (1234)(5678), as it is easier to make a mistake doing long multiplication when the number of digits is bigger.

Yes. Numerically it's the same as multiplying by a positive number. Only the sign of the answer will be different. If you multiply a positive number by a negative number, the product will be negative. If you multiply a negative number by a negative number, the product will be positive. When you multiply more than two numbers together, if you are multiplying an odd number of negatives, the product will be negative. If you are multiplying an even number of negatives, the answer will be positive. (The positive numbers don't affect the sign of the product.)

(6)(8) is the same thing as adding eight 6's together. (6)(8) = 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 = 48.