2nd Grade Adding and Subtracting Within 1,000 Lesson (Free PDF)
This grade 2 add subtract 1000 lesson for 2nd Grade covers adding and subtracting within 1,000 (Common Core 2.NBT.B.7, 2.NBT.B.8), with a free PDF to print.
To add or subtract within 1,000, work one place at a time, starting with the ones. Regroup 10 ones as 1 ten, or 10 tens as 1 hundred, when a place has too many or too few. To add or subtract 10 or 100 mentally, change only the tens digit or the hundreds digit. Check by using the opposite operation.
Grade 2 · Common Core State Standards: 2.NBT.B.7, 2.NBT.B.8
Key facts in this grade 2 add subtract 1000 lesson
- Add and subtract ones first, then tens, then hundreds.
- 10 ones make 1 ten and 10 tens make 1 hundred.
- Trade a ten or a hundred when a place does not have enough to subtract.
- Adding or subtracting 10 changes only the tens digit.
- Adding or subtracting 100 changes only the hundreds digit.
What does it mean to add and subtract within 1,000?
Three-digit numbers have hundreds, tens, and ones. Within 1,000 means the numbers and the answer stay at 1,000 or less. You add or subtract one place at a time, starting with the ones.
How do you add three-digit numbers?
Look at \(258 + 367\). The picture shows each number as flats (hundreds), rods (tens), and cubes (ones).
- Add the ones: \(8 + 7 = 15\). Regroup 10 ones as 1 ten, and keep 5 ones.
- Add the tens: \(5 + 6 + 1 = 12\). Regroup 10 tens as 1 hundred, and keep 2 tens.
- Add the hundreds: \(2 + 3 + 1 = 6\).
- The sum is \(625\).
How do you subtract three-digit numbers?
Take \(432 – 175\). There are 2 ones, and 5 must come off, so trade a ten for ten ones. Then there are 2 tens left, and 7 must come off, so trade a hundred for ten tens.
Now 432 is 3 hundreds, 12 tens, and 12 ones. Subtract each place: \(12 – 5 = 7\) ones, \(12 – 7 = 5\) tens, and \(3 – 1 = 2\) hundreds. The difference is \(257\). Check: \(257 + 175 = 432\).
How can you add or subtract 10 or 100 in your head?
Adding 10 raises the tens digit by 1. Adding 100 raises the hundreds digit by 1. The other digits stay the same.
| Move | Digit that changes | Example |
|---|---|---|
| Add 10 | tens | \(346 + 10 = 356\) |
| Subtract 10 | tens | \(346 – 10 = 336\) |
| Add 100 | hundreds | \(346 + 100 = 446\) |
| Subtract 100 | hundreds | \(346 – 100 = 246\) |
Why do these methods work?
Each place has its own value, so you can add or subtract place by place. Regrouping only renames amounts: 15 ones and 1 ten 5 ones are the same number. Adding 10 means one more ten, so only the tens digit grows. Subtraction undoes addition, so adding the answer to the number taken away checks your work.
Grade 2 add subtract 1000 lesson: questions and answers
How do you add three-digit numbers?
Add the ones, then the tens, then the hundreds. If a place makes 10 or more, regroup: 10 ones become 1 ten, and 10 tens become 1 hundred. For 258 + 367, the sum is 625.
How do you subtract with a zero in the tens place?
Trade a hundred for 10 tens first, then trade one of those tens for 10 ones. For 403 – 158, 403 becomes 3 hundreds, 9 tens, and 13 ones.
What is the shortcut for adding 100?
Add 1 to the hundreds digit and leave the tens and ones alone. So 629 + 100 = 729. The shortcut works because 100 is exactly one more hundred.
How can I check my answer?
Use the opposite operation. After subtracting, add the difference to the number you took away and see if you get the start. After adding, subtract one addend from the sum.
Why does regrouping not change a number?
Regrouping only trades equal amounts. 1 hundred and 10 tens are the same value, so the number stays the same while the places look different.
How to use this grade 2 add subtract 1000 lesson
Read the definitions first, then follow the worked method line by line and redo the example on paper without looking. When every step makes sense, move on to the worksheet, then check yourself with the quiz.
Download the grade 2 add subtract 1000 lesson as a PDF with the button below and keep it with your notes.
Download the grade 2 add subtract 1000 lesson as a PDF with the button below and keep it with your notes.
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