Find the least common multiple of 90 and 20. The least common multiple of 90 and 20 is (Type a whole number.)

Step 1 ：The least common multiple (LCM) of two numbers is the smallest number that is a multiple of both of the numbers. To find the LCM of 90 and 20, we can use the formula LCM(a, b) = abs(a*b) // gcd(a, b), where gcd(a, b) is the greatest common divisor of a and b.

Step 2 ：Let's assign the values: a = 90 and b = 20.

Step 3 ：By substituting the values into the formula, we get the least common multiple (lcm) as 180.

Step 4 ：Final Answer: The least common multiple of 90 and 20 is \(\boxed{180}\).