math help

What is 21/33 + 2/10?

What is 21/33 + 2/10?

This is how we add

21
33
+
2
10

Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

Now you multiply 21 by 10, and get 210, then we multiply 33 by 10 and get 330.

21/33 times 10

Do the same for the second term. We multiply 2 by 33, and get 66, then multiply 33 by 10 and get 330.

2/10 times 33

The problem now has new fractions to add:

210
330
+
66
330

Step 2

Since our denominators match, we can add the numerators.

210 + 66 = 276

This yields the answer

276
330

Step 3

The last step is to reduce the fraction if we can.

To find out, we try dividing it by 2...

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

276
330
÷ 2 =
138
165

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

138
165
÷ 3 =
46
55

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

Nope! So now we try the next greatest prime number, 41...

Nope! So now we try the next greatest prime number, 43...

Nope! So now we try the next greatest prime number, 47...

No good. 47 is larger than 46. So we're done reducing.

There you have it! Here's the final answer to 21/33 + 2/10

21
33
+
2
10
=
46
55
© 2014 Randy Tayler