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Carrying and Regrouping Values in AdditionSometimes your addition problems give you an answer that is greater than ten (10). For example, 6 + 6 = 12. When you start to add larger numbers, you will need to start "carrying" values. When we learned about addition, we used the term carry. Today, many math teachers use the term "regrouping". Carrying and regrouping are the same ideas. When you wind up with a value greater than ten, you need to add some extra to the column to the left. You are regrouping values. To be honest, we prefer the term carry, but you need to say the word your teacher wants to hear.
4 + 4 = 8 (no carrying/regrouping)
8 + 8 = 16 (no carrying/regrouping)
16 + 16 = 32 (carrying/regrouping needed)
- or -
How did we get that answer? Why did you need to carry? Shouldn't the answer be 20-something? There are two ones in the tens columns and those add up to "2". When you solve the problem, your first step is to add the 6+6 in the right column to get twelve (12). Since the sum from the ones column is greater than nine (9), you need to bring (carry) the ten over to the next column to the left (the tens column). You get "3" as the sum of the tens column because you carried the value from the ones column when you were adding your first set of numbers.
Here are the steps...
(1) Add the values in the ones column. In our example you add 6 + 6. The answer is "12".
(2) Write down the "2". That will be the ones value in your sum.
(3) Take that extra "1" and add it to the values in the tens column. Moving that "1" is called carrying or regrouping. In our example you would then add 1 + 1 + 1 for the tens column.
(4) You would get the tens sum of "3" and that becomes the tens column in your answer.
(5) The two values (3 and 2) make up your sum.
Always Moving to the LeftJust a little reminder. As you add up numbers that are greater than 9, you will add to the left. When you add multiple columns, you always start with the smallest values. If you have a five-digit number such as 12,345, you would start adding values in the ones column first. Then you would move to the tens, hundreds, thousands, and ten thousands columns. If carrying or regrouping was involved, you would take the carried value and place it in the column to the left. So, if you were adding numbers in the tens column and you needed to carry a "1", you would place that "1" in the hundreds column.
• Start with the ones column: 9+9=18
• Since that sum is greater than nine, you need to carry the one (1) to the next column to the left.
• Add the values in the tens column (don't forget the carried value): 1+9+9=19
• You got a sum greater than nine again. Carry your extra tens value to the hundreds column.
• Add the values in the hundreds column (don't forget the carried value): 1+9+9=19
• Since you don't have another column, you're done. Write down the nineteen (19)
We built our sum like this... ---8, then --98, then 1998.
Carrying in MultiplicationYou will also use carrying in multiplication. Addition and multiplication are closely linked because they combine values. Addition combines individual amounts while multiplication combines groups. You'll soon learn that when you get values greater than "9" in your multiplication you will need to carry or regroup those values to the next column. Your answers will be much bigger, but the process will be the same.
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