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.
This fills all textboxes with random numbers. If you fill in random numbers yourself, it is very likely that those numbers do not have a solution. To avoid disappointment, use this button instead! It only uses random numbers that do have a solution.
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 |
|---|---|---|---|---|---|---|
| 53 | 157 | 0 | 53 | 0 | 1 | 0 |
| 157 | 53 | 2 | 51 | 1 | 0 | 1 |
| 53 | 51 | 1 | 2 | 0 | 1 | -1 |
| 51 | 2 | 25 | 1 | 1 | -1 | 26 |
| 2 | 1 | 2 | 0 | -1 | 26 | -53 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 549 | 538 | 1 | 11 | 0 | 1 | -1 |
| 538 | 11 | 48 | 10 | 1 | -1 | 49 |
| 11 | 10 | 1 | 1 | -1 | 49 | -50 |
| 10 | 1 | 10 | 0 | 49 | -50 | 549 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 443 | 105 | 4 | 23 | 0 | 1 | -4 |
| 105 | 23 | 4 | 13 | 1 | -4 | 17 |
| 23 | 13 | 1 | 10 | -4 | 17 | -21 |
| 13 | 10 | 1 | 3 | 17 | -21 | 38 |
| 10 | 3 | 3 | 1 | -21 | 38 | -135 |
| 3 | 1 | 3 | 0 | 38 | -135 | 443 |
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 ≡ 499 × 157-1 (mod 53) ≡ 499 × 26 (mod 53) ≡ 42 (mod 53)x ≡ 45 × 538-1 (mod 549) ≡ 45 × 499 (mod 549) ≡ 495 (mod 549)x ≡ 661 × 105-1 (mod 443) ≡ 661 × 308 (mod 443) ≡ 251 (mod 443)
So now we have the following equations of the form x ≡ a (mod m):
x ≡ 42 (mod 53)
x ≡ 495 (mod 549)
x ≡ 251 (mod 443)
Now the actual calculation
- Find the common modulus M
M = m1 × m2 × ... × mk = 53 × 549 × 443 = 12889971 - We calculate the numbers M1 to M3
M1=M/m1=12889971/53=243207,M2=M/m2=12889971/549=23479,M3=M/m3=12889971/443=29097 - 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 -16 mod 53 ≡ 37n b q r t1 t2 t3 53 243207 0 53 0 1 0 243207 53 4588 43 1 0 1 53 43 1 10 0 1 -1 43 10 4 3 1 -1 5 10 3 3 1 -1 5 -16 3 1 3 0 5 -16 53
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is 193 mod 549 ≡ 193n b q r t1 t2 t3 549 23479 0 549 0 1 0 23479 549 42 421 1 0 1 549 421 1 128 0 1 -1 421 128 3 37 1 -1 4 128 37 3 17 -1 4 -13 37 17 2 3 4 -13 30 17 3 5 2 -13 30 -163 3 2 1 1 30 -163 193 2 1 2 0 -163 193 -549
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is -22 mod 443 ≡ 421n b q r t1 t2 t3 443 29097 0 443 0 1 0 29097 443 65 302 1 0 1 443 302 1 141 0 1 -1 302 141 2 20 1 -1 3 141 20 7 1 -1 3 -22 20 1 20 0 3 -22 443
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
= (42 × 243207 × 37 +
495 × 23479 × 193 +
251 × 29097 × 421) mod 12889971
= 11241819 (mod 12889971)
So our answer is 11241819 (mod 12889971).
Verification
So we found that x ≡ 11241819
If this is correct, then the following statements (i.e. the original equations) are true:
157x (mod 53) ≡ 499 (mod 53)
538x (mod 549) ≡ 45 (mod 549)
105x (mod 443) ≡ 661 (mod 443)
Let's see whether that's indeed the case if we use x ≡ 11241819.