Algorithm :

Declare variables for three numbers and variables for sum, difference, and product.

Prompt the user to input three numbers.

Read the input numbers.

Calculate the sum of the three numbers $(a+b+c).$

Display the sum.

Calculate the difference of the three numbers $(a-b-c).$

Display the difference.

Calculate the product of the three numbers $(abc).$

Display the product.

End the program.

If can, make the flowchart using yEd, Thank you