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What is 87/100 - 4/11?

What is 87/100 - 4/11?

Here's how to subtract 4/11 from 87/100:

87
100
4
11

Step 1

We can't subtract two fractions with different denominators. So you need to get a common denominator. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 87 by 11, and get 957.

Then we multiply 4 by 100, and get 400.

Next we give both terms new denominators -- 100 × 11 = 1100.

So now our fractions look like this:

957
1100
400
1100

Step 2

Since our denominators match, we can subtract the numerators.

957 − 400 = 557

So the answer is:

557
1100

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

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

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

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...

Nope! So now we try the next greatest prime number, 53...

Nope! So now we try the next greatest prime number, 59...

Nope! So now we try the next greatest prime number, 61...

Nope! So now we try the next greatest prime number, 67...

Nope! So now we try the next greatest prime number, 71...

Nope! So now we try the next greatest prime number, 73...

Nope! So now we try the next greatest prime number, 79...

Nope! So now we try the next greatest prime number, 83...

Nope! So now we try the next greatest prime number, 89...

Nope! So now we try the next greatest prime number, 97...

Nope! So now we try the next greatest prime number, 101...

Nope! So now we try the next greatest prime number, 103...

Nope! So now we try the next greatest prime number, 107...

Nope! So now we try the next greatest prime number, 109...

Nope! So now we try the next greatest prime number, 113...

Nope! So now we try the next greatest prime number, 127...

Nope! So now we try the next greatest prime number, 131...

Nope! So now we try the next greatest prime number, 137...

Nope! So now we try the next greatest prime number, 139...

Nope! So now we try the next greatest prime number, 149...

Nope! So now we try the next greatest prime number, 151...

Nope! So now we try the next greatest prime number, 157...

Nope! So now we try the next greatest prime number, 163...

Nope! So now we try the next greatest prime number, 167...

Nope! So now we try the next greatest prime number, 173...

Nope! So now we try the next greatest prime number, 179...

Nope! So now we try the next greatest prime number, 181...

Nope! So now we try the next greatest prime number, 191...

Nope! So now we try the next greatest prime number, 193...

Nope! So now we try the next greatest prime number, 197...

Nope! So now we try the next greatest prime number, 199...

Nope! So now we try the next greatest prime number, 211...

Nope! So now we try the next greatest prime number, 223...

Nope! So now we try the next greatest prime number, 227...

Nope! So now we try the next greatest prime number, 229...

Nope! So now we try the next greatest prime number, 233...

Nope! So now we try the next greatest prime number, 239...

Nope! So now we try the next greatest prime number, 241...

Nope! So now we try the next greatest prime number, 251...

Nope! So now we try the next greatest prime number, 257...

Nope! So now we try the next greatest prime number, 263...

Nope! So now we try the next greatest prime number, 269...

Nope! So now we try the next greatest prime number, 271...

Nope! So now we try the next greatest prime number, 277...

Nope! So now we try the next greatest prime number, 281...

Nope! So now we try the next greatest prime number, 283...

Nope! So now we try the next greatest prime number, 293...

Nope! So now we try the next greatest prime number, 307...

Nope! So now we try the next greatest prime number, 311...

Nope! So now we try the next greatest prime number, 313...

Nope! So now we try the next greatest prime number, 317...

Nope! So now we try the next greatest prime number, 331...

Nope! So now we try the next greatest prime number, 337...

Nope! So now we try the next greatest prime number, 347...

Nope! So now we try the next greatest prime number, 349...

Nope! So now we try the next greatest prime number, 353...

Nope! So now we try the next greatest prime number, 359...

Nope! So now we try the next greatest prime number, 367...

Nope! So now we try the next greatest prime number, 373...

Nope! So now we try the next greatest prime number, 379...

Nope! So now we try the next greatest prime number, 383...

Nope! So now we try the next greatest prime number, 389...

Nope! So now we try the next greatest prime number, 397...

Nope! So now we try the next greatest prime number, 401...

Nope! So now we try the next greatest prime number, 409...

Nope! So now we try the next greatest prime number, 419...

Nope! So now we try the next greatest prime number, 421...

Nope! So now we try the next greatest prime number, 431...

Nope! So now we try the next greatest prime number, 433...

Nope! So now we try the next greatest prime number, 439...

Nope! So now we try the next greatest prime number, 443...

Nope! So now we try the next greatest prime number, 449...

Nope! So now we try the next greatest prime number, 457...

Nope! So now we try the next greatest prime number, 461...

Nope! So now we try the next greatest prime number, 463...

Nope! So now we try the next greatest prime number, 467...

Nope! So now we try the next greatest prime number, 479...

Nope! So now we try the next greatest prime number, 487...

Nope! So now we try the next greatest prime number, 491...

Nope! So now we try the next greatest prime number, 499...

Nope! So now we try the next greatest prime number, 503...

Nope! So now we try the next greatest prime number, 509...

Nope! So now we try the next greatest prime number, 521...

Nope! So now we try the next greatest prime number, 523...

Nope! So now we try the next greatest prime number, 541...

Nope! So now we try the next greatest prime number, 547...

Nope! So now we try the next greatest prime number, 557...

Nope! So now we try the next greatest prime number, 563...

No good. 563 is larger than 557. So we're done reducing.

There you have it! The final answer is:
87
100
4
11
=
557
1100