208k views
1 vote
21/25-81/100 help pleaseee​

2 Answers

0 votes

Answer:

3/100 (Decimal Form: 0.03)

Explanation:

Find the Least Common Denominator (LCD) of 21/25 , 81/100. In other words, find the Least Common Multiple (LCM) of 25,100.

Method 1: By Listing Multiples

- List the multiples of each number.

Multiples of 25 : 25, 50, 75, 100, ...

Multiples of 100 : 100, ...

- Find the smallest number that is shared by all rows above. This is the LCM.

LCM is 100.

Method 2: By Prime Factors

- List the prime factors of each number.

Prime Factors of 25 : 5, 5

Prime Factors of 100 : 2, 2, 5, 5

- Find the union of these primes.

2, 2, 5, 5

- Multiply these numbers: 2 * 2 * 5 * 5 = 100. This is the LCM.

LCM = 100

Make the denominators the same as the LCD.

21 * 4/25 * 4 - 81/100

Simplify. Denominators are now the same.

84/100 - 81/100

Join the denominators.

84-81/100

Simplify.

3/100 (Decimal Form: 0.03)

User Aadit M Shah
by
7.6k points
1 vote

Answer:

3/100

Explanation:

21/25 turns into 84/100, so that the two digits have the same denominator. Then subtract. The answer is 3/100, and cannot be simplified

User Audwin
by
8.4k points

No related questions found