January 24, 2017

by Robert

0 comments

4100+5200=9300

First I did 100+200 in my head.

Then I did 4000+5000 in my head.

then I added up the answers to get the answer of 9300.

I did this because there was no carrying over to do.

9400+4400=13800

First I did 9+4 to get 13 but its 9000 and 4000 so I added on the three zeros.

Then I did 400+400 wich is 800.

Finally I added them all together to get 13800

I did this because there was carrying in this sum.

7400+2900=10300

First I did 9+4=13 wich if I add the two zeros on the end makes 1300

Then I did 7000+2000=9000

Next I added 9000+1300 but I would need to carry over to the ten thousands so I carried over to the ten thousands to get 10300

I chose this because this sum had lots of carrying over in it. Working with smaller number to carry is easier than thousands then all you have to do is add the extra zeros on end. Then your carrying is complete and you can carry on with your sum

The most important things are:

To think if you might need carrying to complete the calculation

To find a suitable method to use in your head

To not choose sums that are too hard for yourself unless you want a challenge everyone likes a challenge sometimes but not always