1.4 factors
A factor of a whole number divides into it without a remainder.
This means that 1 is a factor of every number. Every number is a factor of itself.
Example
Work out all the factors of 40 and 36
Answer:
1×40 = 40 1×36 = 36
2×20 = 40 2×18 = 36
4×10 = 40 3×12 = 36
5×8 = 40 4×9 = 36
6×6 = 36
start with 1 then try 2,3,4,...1 and 40 both factors. 2 and 20 are both factors. 3 is not a factor. 40÷3 has a reminder. 4 and 10 are factors. 5 and 8 are factors. You can stop now. You dont need to try 8 because it is already in the list of factors.
The factors of 40 are 1,2,4,8,10, and 40
Exercise 1.4
1. The number 18 has six factors. Two of these factors are 1 and 18. Find the other four.
2. Find all the factors of each of each number
a. 15 c. 24 e.49
b. 18 d. 36 f. 56
3. Find the common factors of each pair of numbers
a. 6 and 10 d. 6 and 72
b. 4 and 12 e. 36 and 9
C. 40 and 25 f. 100 and 20
4. The number 45 has 3 factors. What are they?
5. The number 100 has 8 factors. What are they?