Answer
$70$
Work Step by Step
Step 1. Write the prime factorization of each number.
Step 2. Write the product containing each different prime factor (from Step 1) the greatest number of times that it appears in any one factorization. This product is the LCM.
$2=2$
$5=5$
$7=7$
$LCM=2*5*7=70$