Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Grade 1 MAP 2 D Trimester 2 Instructional Strategies Regrouping in Addition Aligned to the 1997 California Content Standards
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Addition with Regrouping 2 digits + 1 digit Write the 2 digits + 1 digit problem horizontally. Students rewrite the problem in working form while reading the problem aloud splitting the tens and ones in the two digit number. Ex. 35+8= Three tens, five ones 3 5 Down and to the left plus eight ones + 8 Equals IAATF Trimester 2 Addition with Regrouping2 digits + 1 digit Page 1
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Begin adding in the ones column Ask these questions: Is the sum greater than 9? Is the sum a two digit number? Can the sum be split into tens and ones? If NO, then write the sum and bring down the tens. IAATF Trimester 2 Addition with Regrouping2 digits + 1 digit Page 2
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 If the answer was YES, then REGROUP Orally split the sum into tens and ones while writing so the 1 ten is written FIRST and then the 3 ones. 1 Ex One tens three ones IAATF Trimester 2 Addition with Regrouping2 digits + 1 digit Page 3 Is the sum greater than 9? Is the sum a two digit number? Can the sum be split into tens and ones?
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Add the tens column Rewrite the sum with the digits together IAATF Trimester 2 Addition with Regrouping2 digits + 1 digit Page 4
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Addition with Regrouping 2 digits + 2 digits Rewrite the problem vertically while reading it aloud, splitting the tens and ones in both numbers. Ex = Three tens, five ones 3 5 Down and to the left plus four tens eight ones Equals IAATF Trimester 2 Addition with Regrouping2 digits + 2 digit Page 1
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Add the ones column Ask these questions: Is the sum greater than 9? Is the sum a two digit number? Can you split the sum into tens and ones? If NO, then write the sum and add the tens column. IAATF Trimester 2 Addition with Regrouping2 digits + 2 digit Page 2
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 If the answer to these questions is YES, then REGROUP. Orally split the sum into tens and ones while writing each digit. Regroup and write the 1 ten FIRST, then write the 3 ones. 1 Ex Add the tens column. Add the 2 digits in the tens place from the problem first, then add the 1 ten that was regrouped. Orally chant tens plus 4 tens equals 7 tens plus one more ten equals 8 tens. IAATF Trimester 2 Addition with Regrouping2 digits + 2 digit Page 3
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Addition with Regrouping 3 digits + 3 digits Follow the same procedures as in the previous slide (2 digits + 2 digits) for regrouping into the tens column. Ask the question: Is the sum (in the tens column) a two digit sum? 1 Ex If NO, then write the sum and add the hundreds column. IAATF Trimester 2 Addition with Regrouping3 digits + 3 digit Page 1
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 If the answer is YES… Write the sum and write a 0 in the ones place and orally read the sum for the tens column Regroup by orally saying and regrouping the one hundred in the hundreds column first then writing the 2 tens in the tens column. Remember regroup into the hundreds column first. One hundred Two tens One hundred twenty 4 tens plus 7 tens equals 11 tens plus 1 more ten equal 12 tens altogether. 12 tens is 120. IAATF Trimester 2 Addition with Regrouping3 digits + 3 digit Page 2
Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 1 Add the hundreds column Rewrite the sum with the digits together IAATF Trimester 2 Addition with Regrouping3 digits + 3 digit Page 3