Question

How do you know that 35×5=5×35 without finding products

Answer 1

Multiplication (like addition) has the same answer whatever the order.  2 X 3 = 6.  3 X 2 = 6. 

Answer 2

You know it because they are the same thing. 35x5 is something you can do both ways. You can check on a calculator. Do the question both ways and you will get the same product.