ADDING FRACTIONS - Denominator confusion?
When fractions have the same denominators they are much easier to add together, it is just a case of adding numerators and then the denominators are kept the same. For example, five ninths plus two ninths is equal to seven ninths (5/9 + 2/9 = 7/9) as the diagram below demonstrates:
When the denominator is different this is where it can get a little tricky. For example, one quarter plus three eighths (1/4 + 3/8); the denominators are not the same! This is where equivalent fractions are helpful, you need to find a number to multiply one of the fractions so that both fractions to be added together have the same denominator.
As for the example; 1/4 + 3/8, 2 would be a good number to use as 4 x 2 is equal to 8. Now since we multiplied the denominator by 2, then we must also multiply the numerator by 2. So 1 x 2 is equal to 2 and below is a diagram to help with any confusion you may have:
As for the example; 1/4 + 3/8, 2 would be a good number to use as 4 x 2 is equal to 8. Now since we multiplied the denominator by 2, then we must also multiply the numerator by 2. So 1 x 2 is equal to 2 and below is a diagram to help with any confusion you may have:
Activity – Paper Folding
Materials Needed:
*Paper
*Lead pencil
*Coloured pencils
Part 1 - Add half and a third.
To do this you will need to fold the sheet of paper into two halves (fold once in half, then fold that half in half) in one direction (DO NOT TURN PAPER AROUND), and then three thirds (2 equal folds at the same time) in the other direction.
Then answer these questions:
How many equal parts?
How many equal parts in one half?
How many equal parts in one third?
How many in a half and a third?
TIP: Use a different colour pencil to answer each of the questions by shading the parts.
Your answers to these questions should help you to answer how much a half plus a third is!
Part 2 - Can you make your own question for another class member to complete? Try to only use halves, quarters and thirds in you question, so it is not too tricky!
Materials Needed:
*Paper
*Lead pencil
*Coloured pencils
Part 1 - Add half and a third.
To do this you will need to fold the sheet of paper into two halves (fold once in half, then fold that half in half) in one direction (DO NOT TURN PAPER AROUND), and then three thirds (2 equal folds at the same time) in the other direction.
Then answer these questions:
How many equal parts?
How many equal parts in one half?
How many equal parts in one third?
How many in a half and a third?
TIP: Use a different colour pencil to answer each of the questions by shading the parts.
Your answers to these questions should help you to answer how much a half plus a third is!
Part 2 - Can you make your own question for another class member to complete? Try to only use halves, quarters and thirds in you question, so it is not too tricky!
Try this game out, for practice with adding fractions:
http://www.mathplayground.com/FractionGame/FractionGame.html
http://www.mathplayground.com/FractionGame/FractionGame.html