guardian_owl
CAGiversary!
- Feedback
- 26 (100%)
So after hearing so many parents push back against common core mathematics finally saw a video which explained the common core method of addition and I don't get what the big
ing deal is.
Rather than memorizing what X + Y is or using long addition which is difficult to do in your head, you break the two numbers into smaller numbers to make as many numbers as possible evenly divisible by 10 to make it easier to visualize.
So 66 + 25 becomes 60+6 + 4+21. 6 matches with 4 to make 10 and it becomes 60 + 10 + 21, so you have 60 + 10 + 20 with a remainder of 1, for 91. Once you became more comfortable with the method what you would probably do is just subtract 4 from 25 and add that 4 to 66 in your first step to get 70 + 21.
Or something like 64 + 43 it becomes 60+4 + 3+40. So you have 60 + 40 with a remainder of 7, for 107.

Rather than memorizing what X + Y is or using long addition which is difficult to do in your head, you break the two numbers into smaller numbers to make as many numbers as possible evenly divisible by 10 to make it easier to visualize.
So 66 + 25 becomes 60+6 + 4+21. 6 matches with 4 to make 10 and it becomes 60 + 10 + 21, so you have 60 + 10 + 20 with a remainder of 1, for 91. Once you became more comfortable with the method what you would probably do is just subtract 4 from 25 and add that 4 to 66 in your first step to get 70 + 21.
Or something like 64 + 43 it becomes 60+4 + 3+40. So you have 60 + 40 with a remainder of 7, for 107.
Last edited by a moderator: