What are the factor pairs of 40?

The pairs are (1, 40), (2, 20), (4, 10) and (5, 8). Each pair multiplies to 40.

What is the greatest common factor of 40 and 60?

The GCF of 40 and 60 is 20. The common factors are 1, 2, 4, 5, 10 and 20, and 20 is the largest.

Factors of 40 - Factor Pairs & Prime Factorization

Q: What are the factors of 40?

The factors of 40 are 1, 2, 4, 5, 8, 10, 20 and 40. That is eight factors, and each one divides 40 exactly.

Q: What is the prime factorization of 40?

40 = 2 × 2 × 2 × 5 = 2³ × 5. Its prime factors are 2 and 5.

What Are the Factors of 40?

Picture 40 students in a gym. You can line them up in 1 row of 40, 2 rows of 20, 4 rows of 10, 5 rows of 8, or flip any of those around. Every tidy layout is a factor. A factor is a whole number that divides another number exactly, with no remainder.

The factors of 40 are 1, 2, 4, 5, 8, 10, 20 and 40. That is eight factors.

Factor Pairs of 40

Look for pairs that multiply to 40, from the outside in.

Handwritten notebook page titled Factors of 40 showing 1 × 40, 2 × 20, 4 × 10 and 5 × 8 all equal to 40, with the eight factors circled in red and the note 8 factors — The four pairs of 40, with every factor circled.

Start with 1 × 40.
Try 2. Since 40 ÷ 2 = 20, write 2 × 20.
Try 3. It leaves a remainder, so skip it.
Try 4. Since 40 ÷ 4 = 10, write 4 × 10.
Try 5. Since 40 ÷ 5 = 8, write 5 × 8.
Try 6 and 7. Neither divides 40, and the next number, 8, is already used, so you are done.

Prime Factorization of 40

Prime factors show what 40 is built from. Split it and keep going until every branch is prime.

Handwritten factor tree of 40 splitting into 4 and 10, then 4 into 2 and 2 and 10 into 2 and 5, with the primes circled in red and 40 = 2 × 2 × 2 × 5 = 2³ × 5 written below — Factor tree of 40. The circled primes are 2, 2, 2 and 5.

So 40 = 2 × 2 × 2 × 5 = 2³ × 5. Its prime factors are 2 and 5. Add 1 to each exponent and multiply: (3 + 1) × (1 + 1) = 8, which matches the list.

Divisibility check for 40

A number divides by 40 when it divides by both 8 and 5. It must end in 0 or 5, and its last three digits must be a multiple of 8. For 120, the last digit is 0 and 120 ÷ 8 = 15, so 120 is a multiple of 40.

Is 40 a Prime or Composite Number?

Composite. It has eight factors. The sum of all factors is 1 + 2 + 4 + 5 + 8 + 10 + 20 + 40 = 90.

Real-Life Uses of the Factors of 40

A work week. Forty hours splits into 5 days of 8 hours or 4 days of 10 hours.
Sharing. Forty chocolates share evenly between 2, 4, 5, 8 or 10 people.
Money. A 40-dollar total can be paid as two 20s, four 10s or eight 5s.

Common Factors of 40 With Other Numbers

The factors of 60 include 1, 2, 4, 5, 10 and 20 among others, so 40 and 60 share 1, 2, 4, 5, 10 and 20. The GCF is 20, which simplifies 40/60 to 2/3.

Quick Practice

Which of these are factors of 40: 5, 6 or 8? That is 5 and 8. Now try 80 and check it with the calculator.

Factors of 40