Chat with our AI personalities
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. These problems might be easier to visualize if you copy them 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
22+14+8
The patterns and properties to compute mentally 120 times 30 is the numbers 12 and 3 plus the two 0. Multiply 12 by 3 (36) and add the two 0 (3600).
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. These problems might be easier to visualize if you copy them vertically. Example: 56 - 39 Just looking at it, you might think there's a problem with subtracting nine from six until you realize that 56 is 5 tens and 6 ones which is the same thing as 4 tens and 16 ones. Now you can subtract 9 from 16, leaving 7 in the ones place and 3 from 4, (the regrouped 5) leaving 1 in the tens place. 56 - 39 = 17 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
"Regrouping" is a more modern word for "borrowing". When subtracting with decimals, if you are trying to subtract a larger digit from a smaller digit, you "regroup" the next digit to the left by taking one away from it and adding 10 to the number you are subtracting from. Example 84 - 19 _____ You can't subtract 9 from 4, so you take one away from the next digit over (the 8) and add 10 to the 4. 14 - 9 is 5 in the ones digits 7 - 1 is 6 in the tens digits Now if you are subtracting mixed numbers, the regrouping process is essentially the same, except that instead of always regrouping by tens, we regroup by the denominator size. 8 1/5 - 3 3/5 ______ We can't subtract 3/5 from 1/5, so we regroup one unit from the 8 into 5 fifths. 7 6/5 -3 3/5 _______ 4 3/5 It is very easy when you get some practice doing it.