Today, we are going to learn about adding fractions.
Have a look at the in focus question below.
How much chocolate is being shared?
Do you think it is true that 1/3 + 1/9 = 2/9? How can you tell?
If you have the look at the image in the lets learn, you can see that the above statement is not true. They are not the same.
What we do know is that 1/9 + 3/9 = 4/9. This is the amount being eaten.
There are 9 pieces of chocolate. The girl is having 1 piece from the 9 pieces and the boy is having 3 pieces of chocolate from the 9 pieces.
We can convert 1/3 of the bar to 3/9. These fractions are equivalent.
We know these are equivalent because if we multiply both the top and bottom by 3 we get 3/9.
Now have a look at Q2 at the top.
To find the total, what do you think you need to do? Are the denominators the same?
How could we make them the same?
Do you notice that 5 and 10 can share the same denominator?
If we convert all the fractions so they share the same denominator, we know that 1/5 can be converted to 2/10 by multiplying both the numerator and denominator by 2.
Now, have a go at changing 2/5 so it shares the denominator of 10.
Well done if you got the answer 4/10.
Now we can add them and it is so much easier because they all share the same denominator of 10.
If we add 2/10, 3/10 and 4/10 we get the answer 9/10.
Now have a go at the guided practice section above.
Remember if the denominator is not the same use your times tables to make them the same. This will make it much easier for you!
Lets work out Q1b in the guided practice section together.
We need to add 1/10 and 1/5.
You can see that the denominators (the numbers at the bottom) are not the same so we need to make them the same before we can add them together.
You should know that 5 and 10 share the same multiples therefore we can convert 1/5 into tenths.
How do you think we can do this?
Look at my example I have found that 5 x 2 is 10 so if I multiply the top number by 2 as well I have changed 1/5 into 2/10.
Below is worksheet 8 which your teacher has sent you on Seesaw. Please complete it on Seesaw and send it back to your teacher on Seesaw who will then send you some feedback.