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Why is multiplying a number by 200 the same as multiplying it by 100 and then by 2?
Wiki User
∙ 12y ago
When you multiply three numbers together you can either multiply the first two together and multiply the result of that by the third, or multiply the last two together and multiply the result of that by the first.1
200 = 100 x 2
So, for example:
5 x 200 = 5 x (100 x 2)
= 5 x 100 x 2
= (5 x 100) x 2
Meaning that multiplying by 200 is the same as multiplying by 100 and then by 2.
1This is the "Associative Law". Using smaller numbers as an example:
Suppose you have 2 x 3 x 4.
It says:
2 x 3 x 4 = (2 x 3) x 4
= 6 x 4
= 24
or:
2 x 3 x 4 = 2 x (3 x 4)
= 2 x 12
= 24
As multiplication is short hand for repeated addition, this can be seen by using only additions:
2 x 3 is the same a 3 + 3 (adding 3 to itself two times, that is twice 3) or 2 + 2 + 2 (adding 2 to itself three times, that is 2 thrice), the result of all three being 6:
2 x 3 = 6
3 + 3 = 6
2 + 2 + 2 = 6
Now, 2 x 3 x 4 can be calculated as (2 x 3) x 4, that is do 2 x 3 first and then multiply the result of that by 4. In terms of addition, this becomes:
(2 x 3) x 4 = (3 + 3) x 4
= (3 + 3) + (3 + 3) + (3 + 3) + (3 + 3)
= 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3
= 24
Or, it can be calculated as 2 x (3 x 4), that is do 3 x 4 first and then multiply the result of that by 2. In terms of addition, this becomes:
2 x (3 x 4) = 2 x (3 + 3 + 3 + 3)
= (3 + 3 + 3 + 3) + (3 + 3 + 3 + 3)
= 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3
= 24
In both cases the result is the same - adding 3 to itself eight times to get 24.
Wiki User
∙ 12y ago
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Greg has the same number of 1-block 10-blocks and 100-blocks He models an even number that is less than 400 What is the number?
200
200 percent into a fraction is?
2/1, or just the whole number 2. 200% of something means to double the amount by multiplying it by 2.
What number is 100 times greater than 2?
200
Explain how do divide 0.12 by 8?
One way to divide 0.12 by 8 is to write .12 as a fraction. It is 12/100. Now to divide 12/100 by 8 is the same as multiplying 12/100 by 1/8. This is 12x1/100x8=12/800 or3/200. As a decimal this is .015. We can see this by dividing 3 and 200 both by 2 and we have 1.5/100 which is 15/1000.
Number halfway between 100 and 500?
300 Find the difference (500-100=400) then halve the sum(200). Add the halved sum to the lowest number in the equaion(100) or subtract the halved sum(200)from the largest number in the equation(500) one:500-100=400 two:400/2=200 Three: 200+100=300 or 500-200=300
Does 200 square root ever end?
The root of ab is the same as the root of a multiplied by the root of b. So root 200 = root 100 x root 2 root 100 is 10, root 2 is an irrational number. Multiplying 10 by an irrational number gives an irrational number. Therefore, root 200 never ends.
How do you find 40 percent of 200?
Find 1 % of 200 by dividing by 100 and then multiplying this by 40.
What is 200 percent of 17?
The answer is 34! U do it by cross multiplying her is the work! _17___ = ___X___ 100 200
What number is 200 17 percent of?
The answer is 34! U do it by cross multiplying her is the work! _17___ = ___X___ 100 200
What 2 numbers can be rounded to the nearest 10th and 100th and be the same number?
100 + 200
How do you find 80 percent of 200 how do you do the working out?
You need to divide your number with 100 and multiply it with how many percent you want. 200 * 80 / 100 = 160 A shorter way is to multiply your number with 0.8. You'll get the same answer.
How do you find the percent of increase?
Here is an example. You increase something from 200 to 250. First, subtract to get the difference (50). The, divide this difference by the initial number (50 / 200 = 0.25). Finally, convert that into a percentage, by multiplying by 100 (25%).
What is 70 per-cent of 200?
70 per-cent of 200 = -130
Greg has the same number of 1-block 10-blocks and 100-blocks He models an even number that is less than 400 What is the number?
200
200 percent into a fraction is?
2/1, or just the whole number 2. 200% of something means to double the amount by multiplying it by 2.
What number is 100 times greater than 2?
200
What is percentage of a number?
A part of the number that can be either bigger, smaller or equal to it. Example 200 100% of 200 = 200 50% of 200 = 100 150% of 200 = 300
