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 |
|---|---|---|---|---|---|---|
| 751 | 757 | 0 | 751 | 0 | 1 | 0 |
| 757 | 751 | 1 | 6 | 1 | 0 | 1 |
| 751 | 6 | 125 | 1 | 0 | 1 | -125 |
| 6 | 1 | 6 | 0 | 1 | -125 | 751 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 125 | 543 | 0 | 125 | 0 | 1 | 0 |
| 543 | 125 | 4 | 43 | 1 | 0 | 1 |
| 125 | 43 | 2 | 39 | 0 | 1 | -2 |
| 43 | 39 | 1 | 4 | 1 | -2 | 3 |
| 39 | 4 | 9 | 3 | -2 | 3 | -29 |
| 4 | 3 | 1 | 1 | 3 | -29 | 32 |
| 3 | 1 | 3 | 0 | -29 | 32 | -125 |
Source: ExtendedEuclideanAlgorithm.com
| n | b | q | r | t1 | t2 | t3 |
|---|---|---|---|---|---|---|
| 883 | 21 | 42 | 1 | 0 | 1 | -42 |
| 21 | 1 | 21 | 0 | 1 | -42 | 883 |
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 ≡ 281 × 757-1 (mod 751) ≡ 281 × 626 (mod 751) ≡ 172 (mod 751)x ≡ 159 × 543-1 (mod 125) ≡ 159 × 32 (mod 125) ≡ 88 (mod 125)x ≡ 950 × 21-1 (mod 883) ≡ 950 × 841 (mod 883) ≡ 718 (mod 883)
So now we have the following equations of the form x ≡ a (mod m):
x ≡ 172 (mod 751)
x ≡ 88 (mod 125)
x ≡ 718 (mod 883)
Now the actual calculation
- Find the common modulus M
M = m1 × m2 × ... × mk = 751 × 125 × 883 = 82891625 - We calculate the numbers M1 to M3
M1=M/m1=82891625/751=110375,M2=M/m2=82891625/125=663133,M3=M/m3=82891625/883=93875 - 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 -239 mod 751 ≡ 512n b q r t1 t2 t3 751 110375 0 751 0 1 0 110375 751 146 729 1 0 1 751 729 1 22 0 1 -1 729 22 33 3 1 -1 34 22 3 7 1 -1 34 -239 3 1 3 0 34 -239 751
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is 47 mod 125 ≡ 47n b q r t1 t2 t3 125 663133 0 125 0 1 0 663133 125 5305 8 1 0 1 125 8 15 5 0 1 -15 8 5 1 3 1 -15 16 5 3 1 2 -15 16 -31 3 2 1 1 16 -31 47 2 1 2 0 -31 47 -125
Source: ExtendedEuclideanAlgorithm.com
So our multiplicative inverse is -51 mod 883 ≡ 832n b q r t1 t2 t3 883 93875 0 883 0 1 0 93875 883 106 277 1 0 1 883 277 3 52 0 1 -3 277 52 5 17 1 -3 16 52 17 3 1 -3 16 -51 17 1 17 0 16 -51 883
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
= (172 × 110375 × 512 +
88 × 663133 × 47 +
718 × 93875 × 832) mod 82891625
= 72971838 (mod 82891625)
So our answer is 72971838 (mod 82891625).
Verification
So we found that x ≡ 72971838
If this is correct, then the following statements (i.e. the original equations) are true:
757x (mod 751) ≡ 281 (mod 751)
543x (mod 125) ≡ 159 (mod 125)
21x (mod 883) ≡ 950 (mod 883)
Let's see whether that's indeed the case if we use x ≡ 72971838.