Take it step by step, or if you'd rather go the easy way, hit the calculator. Whatever the case, you'd want to do it step by step :
10 × 9 = 90 : You multiply 90 and the next number, and continue.
90 × 1 = 90 : Still a 90. Multiply 90 and 18, which is the next number.
90 × 18 = 1,620 : Multiply this with 18 as well, because that's the last number.
Your final answer is : 29, 160.
