Description

comment calculer le ppcm avec une calculatrice casio ?

To calculate the Least Common Multiple (LCM) or PPCM using a Casio calculator, follow these organized steps based on the calculator’s features:

### 1. Check for Built-in LCM Function
– **Access the Function Menu:** Turn on your calculator and navigate to the « Math » or « Function » menu.
– **Select LCM:** If available, select the LCM function, input the two numbers, and the calculator will display the result.

### 2. Using GCD to Find LCM
If the LCM function is unavailable but the GCD function is present:
– **Calculate GCD:** Use the GCD function to find the greatest common divisor of the two numbers.
– **Apply Formula:** Use the formula LCM(a, b) = |a * b| / GCD(a, b). For example, for numbers 12 and 18:
– GCD(12, 18) = 6
– LCM = (12 * 18) / 6 = 36

### 3. Manual Calculation with Prime Factors
If neither LCM nor GCD functions are available:
– **Prime Factorization:** Break down each number into its prime factors.
– 12 = 2^2 * 3^1
– 18 = 2^1 * 3^2
– **Identify Highest Powers:** Take the highest power of each prime number.
– 2^2 and 3^2
– **Calculate LCM:** Multiply these together: 4 * 9 = 36

### 4. Handling Multiple Numbers
– **Iterative Method:** For more than two numbers, find the LCM of pairs sequentially. For example, for numbers a, b, c:
– Find LCM(a, b) = result
– Then find LCM(result, c)

### 5. Verification
– **Cross-Check:** Verify the result using a different method or an online calculator to ensure accuracy.

### Example Walkthrough
**Example:** Find the LCM of 12 and 18.
– **Using GCD:**
– GCD(12, 18) = 6
– LCM = (12 * 18) / 6 = 36
– **Using Prime Factors:**
– Prime factors of 12: 2^2, 3^1
– Prime factors of 18: 2^1, 3^2
– LCM = 2^2 * 3^2 = 36

### Conclusion
By following these steps, you can efficiently calculate the LCM on your Casio calculator, whether using built-in functions, GCD, or manual prime factorization. Always verify your results for accuracy.