GCF (HCF) of 45 and 90

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What is the Greatest Common Divisor of 45 and 90?

Answer

GCF (HCF) of 45 and 90 is
45

Common factors: 1, 3, 5, 9, 15, 45

45 divides 90 (90 ÷ 45 = 2), so the GCF is the smaller number itself.

45 = 32 × 5

90 = 2 × 32 × 5

Prime4590Lowest power
2—2—
3323232
5555

— = power 0: the prime is not a factor of this number, so it cannot be in the GCF.

GCF = 32 × 5 = 45

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GCF Table

Number 1Number 2GCF
45483
45491
45505
45513
45521
45549
45555
45561
456015
45639
45655
45705
45729
457515
45761
45805
45819
459045
45955
45999
451005
4510515
451089
451179
4512015
451255
4513545
4515015
4518045
4540545

FAQ

What is the Greatest Common Divisor of 45 and 90?

GCF (HCF) of 45 and 90 is 45

How to find the GCF of 45 and 90?

You can find the GCF of 45 and 90 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 45 and 90 is 45.

What prime factors do 45 and 90 share?

The prime factorizations of 45 and 90 have 3 × 3 × 5 in common, and multiplying those shared primes gives 45 — exactly the greatest common factor.

How does the GCF reduce the fraction 45/90?

Divide the numerator and the denominator by the GCF 45: 45 ÷ 45 = 1 and 90 ÷ 45 = 2. So 45/90 in lowest terms is 1/2.

See Also