Answer
$140$
Work Step by Step
Factor each number completely to obtain:
$28= 2\cdot 2\cdot 7
\\35 = 5 \cdot 7$
The different factors that appear in the prime factorization of the given numbers are 2, 5, and 7.
The maximum number of times that each unique factor appears in the factorization is:
For 2: two times
For 5: once
For 7: once
The least common multiple will have two 2s, one 5, and one 7.
Thus, the least common multiple of the given numbers is:
$=2 \cdot 2\cdot 5 \cdot 7
\\= 140$