The product of two numbers is 342.If one of the numbers is 18, work out the value of the other number

Question

The product of two numbers is 342.If one of the numbers is 18, work out the value of the other number

Answer 1

342/18 = 171/9 = 19 = the other number

19 x 18 = 342

Use a calculator, for best results

even then you might punch in the wrong number occasionally.

so for a last check, use the "rule of 9's" sum of digits in the problem = sum of digits in solution

1+9 =10 1+0= 1, multiply 1 by 1+8= 9 = 9

look at the product: 3+4+2 = 9. 9=9. About 9/10 chance there's no mistake