This method works best when both of the numbers you are working with are greater than 10. If you have smaller numbers, you can use a different method to find the least common multiple more quickly. For example, if you need to find the least common multiple of 20 and 84, you should use this method. You want to factor the number into its prime factors; that is, find the prime factors you can multiply together to get this number. One way to do this is by creating a  factor tree. Once you are done factoring, rewrite the prime factors as an equation. For example, 2×10=20{\displaystyle \mathbf {2} \times 10=20} and 2×5=10{\displaystyle \mathbf {2} \times \mathbf {5} =10}, so the prime factors of 20 are 2, 2, and 5. Rewriting as an equation, you get 20=2×2×5{\displaystyle 20=2\times 2\times 5}. Do this in the same way you factored the first number, finding the prime factors you can multiply together to get the number. For example, 2×42=84{\displaystyle \mathbf {2} \times 42=84}, 7×6=42{\displaystyle \mathbf {7} \times 6=42}, and 3×2=6{\displaystyle \mathbf {3} \times \mathbf {2} =6}, so the prime factors of 84 are 2, 7, 3, and 2. Rewriting as an equation, you get 84=2×7×3×2{\displaystyle 84=2\times 7\times 3\times 2}. Write the factors as a multiplication sentence. As you write each factor, cross it off in each numbers factorization equation.  For example, both numbers share a factor of 2, so write 2×{\displaystyle 2\times } and cross out a 2 in each number’s factorization equation. Each number also shares a second 2, so change the multiplication sentence to 2×2{\displaystyle 2\times 2} and cross out a second 2 in each factorization equation. These are the factors you did not cross out when comparing the two groups of factors. Thus, these are factors that the two numbers do not share.  For example, in the equation 20=2×2×5{\displaystyle 20=2\times 2\times 5}, you crossed out both 2s, since these factors were shared with the other number. You have a factor of 5 left over, so add this to your multiplication sentence:...

How would you rephrase that briefly using Vietnamese?
Xét các số của bạn. Phân tích số thứ nhất. Phân tích số thứ hai. Viết các thừa số chung. Thêm toàn bộ thừa số còn lại vào phép nhân. Tính bội chung nhỏ nhất.