Welcome to ChineseRemainderTheorem.com!
Use the calculator below to get a step-by-step calculation of the Chinese Remainder Theory. Just enter the numbers you would like and press "Calculate" .
This removes all numbers from the textboxes, such that you can fill in your own.
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This button is similar to the "Clear everything" button, but only clears the left column.
This is useful if you want your equations to be of the form x ≡ a (mod m) rather than bx ≡ a (mod m).
In that case, it can be especially useful after using the random numbers button.
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Are you ready to view a full step-by-step Chinese Remainder Theorem calculation for the numbers you have entered? Then use this button!
Want to know more?- Read about how to execute the Chinese Remainder Theorem
- Discover different ways to calculate multiplicative inverses
Transform the equations
You used one or more of the fields on the left, so your equations are of the form bx ≡ a mod m.
We want them to be of the form x ≡ a mod m, so we need to move the values on the left to the right side of the equation.
For a more detailed explanation about how this works, see this part of our page about how to execute the Chinese Remainder algorithm.
First, we calculate the inverses of the leftmost value on each row:
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 679 | 606 | 1 | 73 | 0 | 1 | -1 |
| 606 | 73 | 8 | 22 | 1 | -1 | 9 |
| 73 | 22 | 3 | 7 | -1 | 9 | -28 |
| 22 | 7 | 3 | 1 | 9 | -28 | 93 |
| 7 | 1 | 7 | 0 | -28 | 93 | -679 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 611 | 928 | 0 | 611 | 0 | 1 | 0 |
| 928 | 611 | 1 | 317 | 1 | 0 | 1 |
| 611 | 317 | 1 | 294 | 0 | 1 | -1 |
| 317 | 294 | 1 | 23 | 1 | -1 | 2 |
| 294 | 23 | 12 | 18 | -1 | 2 | -25 |
| 23 | 18 | 1 | 5 | 2 | -25 | 27 |
| 18 | 5 | 3 | 3 | -25 | 27 | -106 |
| 5 | 3 | 1 | 2 | 27 | -106 | 133 |
| 3 | 2 | 1 | 1 | -106 | 133 | -239 |
| 2 | 1 | 2 | 0 | 133 | -239 | 611 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 859 | 612 | 1 | 247 | 0 | 1 | -1 |
| 612 | 247 | 2 | 118 | 1 | -1 | 3 |
| 247 | 118 | 2 | 11 | -1 | 3 | -7 |
| 118 | 11 | 10 | 8 | 3 | -7 | 73 |
| 11 | 8 | 1 | 3 | -7 | 73 | -80 |
| 8 | 3 | 2 | 2 | 73 | -80 | 233 |
| 3 | 2 | 1 | 1 | -80 | 233 | -313 |
| 2 | 1 | 2 | 0 | 233 | -313 | 859 |
Source: ExtendedEuclideanAlgorithm.com
Click on any row to reveal a more detailed calculation of each multiplicative inverse.
Now that we now the inverses, let's move the leftmost value on each row to the right of the equation:
x ≡ 886 × 606-1 (mod 679) ≡ 886 × 93 (mod 679) ≡ 239 (mod 679)x ≡ 376 × 928-1 (mod 611) ≡ 376 × 372 (mod 611) ≡ 564 (mod 611)x ≡ 53 × 612-1 (mod 859) ≡ 53 × 546 (mod 859) ≡ 591 (mod 859)
So now we have the following equations of the form x ≡ a (mod m):
x ≡ 239 (mod 679)
x ≡ 564 (mod 611)
x ≡ 591 (mod 859)
Now the actual calculation
- Find the common modulus M
M = m1 × m2 × ... × mk = 679 × 611 × 859 = 356372471 - We calculate the numbers M1 to M3
M1=M/m1=356372471/679=524849,M2=M/m2=356372471/611=583261,M3=M/m3=356372471/859=414869 - We now calculate the modular multiplicative inverses M1-1 to M3-1
Have a look at the page that explains how to calculate modular multiplicative inverse.
Using, for example, the Extended Euclidean Algorithm, we will find that:
So our multiplicative inverse is 264 mod 679 ≡ 264n b q r t1 t2 t3 679 524849 0 679 0 1 0 524849 679 772 661 1 0 1 679 661 1 18 0 1 -1 661 18 36 13 1 -1 37 18 13 1 5 -1 37 -38 13 5 2 3 37 -38 113 5 3 1 2 -38 113 -151 3 2 1 1 113 -151 264 2 1 2 0 -151 264 -679
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is -303 mod 611 ≡ 308n b q r t1 t2 t3 611 583261 0 611 0 1 0 583261 611 954 367 1 0 1 611 367 1 244 0 1 -1 367 244 1 123 1 -1 2 244 123 1 121 -1 2 -3 123 121 1 2 2 -3 5 121 2 60 1 -3 5 -303 2 1 2 0 5 -303 611
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is 92 mod 859 ≡ 92n b q r t1 t2 t3 859 414869 0 859 0 1 0 414869 859 482 831 1 0 1 859 831 1 28 0 1 -1 831 28 29 19 1 -1 30 28 19 1 9 -1 30 -31 19 9 2 1 30 -31 92 9 1 9 0 -31 92 -859
Source: ExtendedEuclideanAlgorithm.com
- Now we can calculate x with the equation we saw earlier
x = (a1 × M1 × M1-1 + a2 × M2 × M2-1 + ... + ak × Mk × Mk-1) mod M
= (239 × 524849 × 264 +
564 × 583261 × 308 +
591 × 414869 × 92) mod 356372471
= 188677364 (mod 356372471)
So our answer is 188677364 (mod 356372471).
Verification
So we found that x ≡ 188677364
If this is correct, then the following statements (i.e. the original equations) are true:
606x (mod 679) ≡ 886 (mod 679)
928x (mod 611) ≡ 376 (mod 611)
612x (mod 859) ≡ 53 (mod 859)
Let's see whether that's indeed the case if we use x ≡ 188677364.