What Divided by 3 Equals 21?
Methods
Setting up the problem:
In a problem like this, the “what” means that we’re working with a variable. The most common variable used in math is “x”. So, we could say what number, x, when divided by 3, equals 21?
Solving What Divided by 3 Equals 21
Here’s how you would set up this question as an equation:
x
3
=
21
\frac{x}{3} = 21
3 x = 21
The goal of the problem is to solve for x. To do this we need to change the equation so that x is alone on one side of the equation.In this case, we can do that by multiplying both sides of the equation by 3, resulting in this equation:
x
=
21
∗
3
x = 21*3
x = 21 ∗ 3
Then we simplify and find our answer:
x
=
63
x = 63
x = 63
So, the answer to the question “What divided by 3 equals 21?” is 63.To prove this, we can take the original problem:
x
3
=
21
\frac{x}{3} = 21
3 x = 21
And insert 63 in the place of x:
63
3
=
21
\frac{63}{3} = 21
3 63 = 21
Because this is true, the answer must be correct.
Practice Other Division Problems Like This One
If this problem was a little difficult or you want to practice your skills on another one, give it a go on any one of these too!
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95 divided by what equals 58?
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What is 6 divided by 1/2?