when you add a number from 3 to 9
You need to regroup when you add the numbers together and they add up to a number that is ten or more. For example: 1 164 +518 _____ 682 If it is over ten, take the first digit of the number and put it above the next number. Then, add that number onto the sum of the other digits underneath it.
When the two numbers have an answer that is greater than or equal to ten.
78 can be regrouped into 6 tens and 18 ones.
8 tens and 4 one
6 + 7 = 13 13 can't fit into the ones place. Regroup 13 ones into one ten and three ones. Leave the three ones in the ones place and carry the one ten over to the tens place.
9 rounds up to 10. You can't put ten tenths in one place, you need to regroup and increase the ones by one.
"Carrying" is now called "regrouping." Example: 45 + 28 5 + 8 is 13, which won't fit in the ones place, so we leave 3 of the ones there and regroup the ten other ones into one ten which we add in the tens column. 1 + 4 + 2 = 7 45 + 28 = 73
Back in the day, regrouping in addition was called "carrying" and regrouping in subtraction was called "borrowing." I think "regrouping" is a better term for all of it. This problem might be easier to visualize if you copy it vertically. Example: 45 + 28 5 + 8 is 13, which won't fit in the ones place, so we leave 3 of the ones there and regroup the ten other ones into one ten which we add in the tens column. 1 + 4 + 2 = 7 45 + 28 = 73
You need to regroup when you have something like 46-39. You would cross out the 6 and make it a 16, because you are taking ten from the 4, then you cross out the 4 then make it a three, then you should get 7.
6+6 7+7 10+8 6+4