List the multiples of each and select the least number which appears in all
Multiples of
10=10,10+10=20,20+10=30,30+10=40,50,60,70,80,90,100,110,120,130,140,150,160,...
Multiples of
15=15,15+15=30,30+15=45,45+15=60,75,90,105,120,135,150,165,...
Multiples of
25=25,25+25=50,50+25=75,75+25=100,125,150,175,200...
Alternatively
HOW TO: FIND THE L.C.M USING THE PRIME FACTORS METHOD
Step 1. Find the prime factorization of each number.
Step 2. Write each number as a product of primes.
Step 3. The L.C.M is the product (multiplication) of each of the prime numbers in its highest power.
Step 1 & 2
10=2×515=3×525=5×5=52Step 3
L.C.M =2×3×52=6×25=150