This grade 3 add subtract 1000 lesson explains adding and subtracting within 1,000 in one printable page, with definitions, a method and a worked example.
To add or subtract within 1,000, line up the digits by place value and work from the ones to the hundreds. Regroup 10 ones as 1 ten, or 1 hundred as 10 tens, when needed. You can also use number line jumps, base-ten blocks, or the standard algorithm, then check with the inverse operation.
Grade 3 Add Subtract 1000 Lesson: key facts
- Add or subtract ones, tens, and hundreds in that order.
- Regroup when ones or tens add to 10 or more, or when there are too few to subtract.
- Addition and subtraction undo each other, so you can check with the inverse.
- Estimating by rounding tells you whether the answer makes sense.
What does it mean to add and subtract within 1,000?
Adding and subtracting within 1,000 means working with numbers up to 999 and getting an answer that is also less than 1,000. Every digit has a place: ones, tens, or hundreds. When you add or subtract, you work with each place and keep the value of every digit in mind.
The blocks show \(243 + 135\). Add the hundreds: \(200 + 100 = 300\). Add the tens: \(40 + 30 = 70\). Add the ones: \(3 + 5 = 8\). The total is \(378\).
Regroup means to trade 10 of one place for 1 of the next place, such as 10 ones for 1 ten. Estimate means to find an answer that is close, usually by rounding. The inverse operation of addition is subtraction, and the other way around.
How can you add with a number line?
Start at the first number. Jump by hundreds, then tens, then ones. Each jump is easy to do in your head.
How do you subtract when you need to regroup?
Suppose Maya has 542 stickers and gives away 278. Follow these steps for \(542 – 278\).
- Look at the ones. \(2\) ones is not enough to take away 8, so regroup 1 ten as 10 ones. Now there are 12 ones and 3 tens.
- Subtract the ones: \(12 – 8 = 4\).
- Look at the tens. 3 tens is not enough to take away 7, so regroup 1 hundred as 10 tens. Now there are 13 tens and 4 hundreds.
- Subtract the tens: \(13 – 7 = 6\).
- Subtract the hundreds: \(4 – 2 = 2\).
The answer is \(264\). Maya has 264 stickers left.
How can you check an answer?
Use the inverse operation. If \(542 – 278 = 264\), then \(264 + 278\) must equal 542. Check: \(264 + 278 = 542\). You can also estimate first. Round 542 to 540 and 278 to 280. Then \(540 – 280 = 260\), which is close to 264.
| Strategy | Best used when |
|---|---|
| Place value blocks | You want to see each place |
| Number line jumps | You want to add or subtract in your head |
| Make a friendly number | One number is close to a hundred, such as 299 |
| Standard algorithm | The numbers are large and you need to regroup |
Adding and Subtracting Within 1,000: frequently asked questions
What does within 1,000 mean?
It means the numbers you add or subtract, and the answer, are all less than 1,000. In third grade the answers have at most three digits.
What is regrouping in addition?
Regrouping means trading 10 of one place for 1 of the next place. If ones add up to 10 or more, trade 10 ones for 1 ten and write the extra ones.
How do you subtract across a zero, like 600 – 257?
Regroup 1 hundred as 10 tens, then regroup 1 ten as 10 ones. Now 600 is 5 hundreds, 9 tens, and 10 ones, so each place can be subtracted. The answer is 343.
How can you check a subtraction answer?
Add the answer to the number you subtracted. The sum must equal the starting number. You can also estimate by rounding both numbers to the nearest ten or hundred.
Which strategy is best for adding two numbers?
Any strategy that gives the correct answer is good. Number line jumps and place value work well for mental math, and the standard algorithm is fast for large numbers.
How to use this grade 3 add subtract 1000 lesson
Use this grade 3 add subtract 1000 lesson before the worksheet, then check what you learned with the quiz.
See every chapter on the Grade 3 math page.