Transcript The Four Methods - Goodleigh Primary

The Four Methods
All you need to know about the
four methods
By Eva
Column addition
• Colum addition is really easy when you
know how to do it. Lets take at this sum
below us.
• HTU ]
• 123
• 235
How to do it
• Write down your sum and label the numbers into
units ten hundreds and thousands. Start adding using
the units and then work up next doing tens ect.. Do it a
bit like this. If you have a carrying one all you have to do
is put the number to the right in the box and then put the
other number below the box into the next column. And
when you do the next sum add it on. A bit like this. So if
you had to carry a 2 you would put it under the box and
add it on to the next sum!!
Subtracting
• Subtracting is a lot like adding you do the
same thing but only take the number away
and remember you don’t carry you borrow
addition is carrying!!
• 123• 112
Column multiplication
• So first write your sum and do 5x5which is 25 so write the 5 in and
carry the 2 over next do 4x5 and because you have the 2 add it on
not times it on remember add it on to the total of that.4x5 is 20 add
the 2 is 22 so you put the 2in the box and them put the other 2 in the
hundreds column because you have nothing else to times it by.
Then when your confident at doing that go on to 3 digit by 2 digit it is
the same so remember you need to times the five by all the
numbers at the top. And one more thing when you carry add it on
not times it on!!!
• tu
• 45
•
5
•
How to do it
• Do 5-4 because there in the unit
• column. So now write your answer in the box
• under the units column. Next do 4-6 but on this
one you have
to borrow. What you need to do is borrow from the 4 so you need to
cross out the four and change it to a 3 and make the other four a 14
because it was a four but you’ve added a 1 to it so it makes it
fourteen. So now you do 6-14
•
•
•
HTU
4 3 14 5
364
0
8
1
Column division
•
So first write your sum as always. Now first see how many 2 go into 2 and
then write it above the box. Then see how many 2 go into 3 but because
you got a remainder 1 you put it next to the four all now you call the 4, 14.
But you still put 1 above the three on the box because 2 goes into 3 once.
Now you do how many 2 go into 14 which is 7 so now you know how to do
column division.
•
117
• 2 2314