Math Adding Fractions

What do you need to have when adding unlike fractions?

• common denominator
• common numerator
• common numerator and denominator

What number could be a common denominator for these two fractions?
2/3   and   3/4

• 3
• 4
• 7
• 12

What number could be a common denominator for these two fractions?
1/5   and   5/6?

• 30
• 11
• 6
• 5

What number could be a common denominator for these two fractions?
3/10   and   1/5

• 5
• 10
• 15
• These numbers do not have a common denominator

What number could be a common denominator for these three fractions?
1/2   and   1/3   and   1/4

• 9
• 8
• 12
• 6

Which of these numbers could NOT be a common denominator for these two fractions?
1/3   and   3/6

• 3
• 6
• 12
• 18

Which of these numbers could NOT be a common denominator for these two fractions?
2/4   and   3/8

• 32
• 12
• 8
• 24

Which of these numbers could NOT be a common denominator for these three fractions?
1/3   and 2/5   and   3/10

• 15
• 30
• 60
• 90

Which of these numbers could NOT be a common denominator for these two fractions?
1/6   and   1/4

• 12
• 18
• 24
• 36

3/9 + 4/9

• 7/18
• 7/9
• 12/9
• 12/81