The short answer
- Common Core math teaches the same arithmetic you learned, but asks kids to understand place value first and use the shortcut (the standard algorithm) later. The answers never change: 52 − 27 is still 25.
- The standard algorithm is still required. The standards call for it in grade 4 (adding and subtracting), grade 5 (multiplying) and grade 6 (dividing).
- The “weird” methods are place-value tools: making ten, number bonds, number lines, partial sums, area models and partial quotients all break numbers into tens and ones.
- To help without confusing your child, ask them to explain the method on the page first, then show your way as a check, not a replacement.
- Common Core is a set of goals, not a curriculum. Your district picks the textbook and the worksheets.
Common Core math homework looks strange to most parents because it shows the steps that the old method hid. When you “carry the one,” you are really moving a ten into the tens column. Common Core worksheets ask children to show that move with number lines, number bonds and boxes before they switch to the fast written method. The answers are the same, and the fast method (the standard algorithm) is still on the list of things kids must master.
Below: what the Common Core standards actually are, six problems solved the old way and the new way side by side, and how to help at the kitchen table without undoing what the teacher is building.
What is Common Core math, exactly?
The Common Core State Standards are a list of what students should know at the end of each grade, not a textbook or a teaching method. They were developed by the National Governors Association Center for Best Practices and the Council of Chief State School Officers and released on June 2, 2010, according to Education Week’s report from the launch. The official site is corestandards.org, and the full standard-by-standard math text is also mirrored at thecorestandards.org, which is where the quotes on this page come from.
How many states still use them? The last solid national count is old: by October 2017, eight states had repealed the standards and 21 more had revised them, mostly in minor ways, Education Week reported, citing an Abt Associates analysis. Many states have since renamed or rewritten their standards while keeping much of the content.
Each standard has a code. “4.NBT.B.5” means grade 4, Number and Operations in Base Ten, cluster B, standard 5. You will sometimes see these codes printed at the top of a worksheet.
What the standards do not decide matters just as much. The official myths-and-facts page puts it plainly: “The Common Core is not a curriculum.” States adopt standards, and districts choose the curriculum, the textbook and the homework. Two schools that both follow Common Core can send home very different worksheets. If a method on a page seems odd, it came from your district’s curriculum, which is built to meet the standard, not from the standard itself.
Do kids still learn the “old way”?
Yes. The standard algorithm is required, just later than many parents expect. The standards build understanding first and the fast written method second. This table shows when each operation’s standard algorithm becomes a grade-level expectation, quoted from the standards:
| Operation | Earlier grades: strategies | Standard algorithm required | Standard |
|---|---|---|---|
| Addition and subtraction within 20 | Counting on, making ten, decomposing (grade 1) | n/a (fact fluency) | 1.OA.C.6 |
| Multi-digit addition and subtraction | Models, drawings, place-value strategies (grades 2–3) | Grade 4: “fluently add and subtract… using the standard algorithm” | 4.NBT.B.4 |
| Multi-digit multiplication | Arrays and area models (grade 4) | Grade 5: “fluently multiply… using the standard algorithm” | 5.NBT.B.5 |
| Multi-digit division | Place-value strategies, partial quotients (grades 4–5) | Grade 6: “fluently divide… using the standard algorithm” | 6.NS.B.2 |
Table: when Common Core expects the standard algorithm. Source: Common Core State Standards for Mathematics (NGA Center and CCSSO), text as published at thecorestandards.org.
So if your third grader is drawing boxes to add three-digit numbers, that is on schedule. The column method is coming.
Six problems, solved the old way and the new way
Each example uses real numbers. Work them yourself once; it makes the worksheet much less mysterious.
1. Making ten (grade 1): 8 + 5
- Old way: memorize 8 + 5 = 13.
- New way: 8 needs 2 more to make 10. Split 5 into 2 + 3. Then 8 + 2 = 10, and 10 + 3 = 13.
- Why: it teaches that 13 is “a ten and 3 ones,” the idea behind every later carry. Standard 1.OA.C.6 lists making ten by name.
2. Number bonds: breaking 13 into parts
A number bond is a small diagram: a circle with 13 at the top, connected to circles with 10 and 3. It just shows a whole and its parts. Kids use it for making ten (above) and for subtraction: 13 − 4 is 13 − 3 − 1, which is 10 − 1 = 9.
3. Subtraction with a number line: 52 − 27
- Old way: 7 is bigger than 2, so borrow from the 5: 12 − 7 = 5, then 4 − 2 = 2. Answer 25.
- New way (counting up): start at 27. Jump +3 to 30, +20 to 50, +2 to 52. Add the jumps: 3 + 20 + 2 = 25.
- Another new way (same difference): add 3 to both numbers so the second one is round: 55 − 30 = 25.
- Why: counting up is how many adults make change in their heads. It also shows that subtraction measures distance between two numbers.
4. Partial sums: 348 + 275
- Old way: 8 + 5 = 13, write 3 carry 1; 4 + 7 + 1 = 12, write 2 carry 1; 3 + 2 + 1 = 6. Answer 623.
- New way: add each place separately. Hundreds: 300 + 200 = 500. Tens: 40 + 70 = 110. Ones: 8 + 5 = 13. Total: 500 + 110 + 13 = 623.
- Why: the “carried 1s” in the old method are exactly the 100 inside 110 and the 10 inside 13.
5. Area model and partial products: 23 × 14
- Old way: 23 × 4 = 92; 23 × 10 = 230; 92 + 230 = 322.
- New way: draw a rectangle. Split one side into 20 and 3, the other into 10 and 4. Fill the four boxes:
| × | 20 | 3 |
|---|---|---|
| 10 | 200 | 30 |
| 4 | 80 | 12 |
Table: area model for 23 × 14. The four partial products add to 322.
200 + 30 + 80 + 12 = 322. Written as a list instead of a box, the same four numbers are called partial products. Standard 4.NBT.B.5 names “rectangular arrays, and/or area models” as ways to explain this.
6. Partial quotients: 156 ÷ 12
- Old way: long division. 12 goes into 15 once, remainder 3; bring down 6; 12 goes into 36 three times. Answer 13.
- New way: take out easy chunks. 12 × 10 = 120, leaving 36. 12 × 3 = 36, leaving 0. Add the chunks: 10 + 3 = 13.
- Why: a child can use any chunk they know (12 × 5 works too). It shows what long division is doing underneath.
Why teach it this way at all?
The goal is number sense: knowing why a method works, so mistakes get caught. A child who only knows “borrow from the next column” can produce 52 − 27 = 35 (subtracting the smaller digit from the larger in each column) and not notice. A child who counts up from 27 knows the answer has to be about 25.
The standards spell this out in the eight Standards for Mathematical Practice, which include making sense of problems and looking for structure. Research summarized by the Institute of Education Sciences also supports the visual side: its practice guide on problem solving in grades 4 to 8 rates teaching students to use visual representations as strong evidence. Our math homework help guide covers that research and a routine for getting unstuck.
The honest caveat: the methods take longer at first, and some curricula introduce several strategies in a short time, which can confuse kids who were fine with one. That is a fair criticism of specific worksheets. It does not mean the arithmetic is wrong.
How parents can help without confusing kids
Ask before you explain. The fastest way to create a fight at homework time is to replace the class method with yours. Try this order instead:
- “Show me how your teacher did it.” Look for a worked example in the notes, textbook or the top of the worksheet.
- Solve it your way silently, so you know the target answer.
- Ask questions about their method: “What is the 20 in this box?” “Where did the 3 jump come from?” Explaining is the learning.
- Use your way as a check: “Let’s see if the old method gets the same number.” Matching answers build confidence in both.
- If you are both stuck, stop. Write a short note to the teacher saying where it broke down. That tells the teacher more than a correct answer copied from a parent.
| Symptom at homework time | Likely cause | What to try |
|---|---|---|
| “That’s not how my teacher does it!” | You switched methods | Let them lead; use your method only to check |
| Right answer, marked wrong | Graded on showing the method | Ask which strategy the assignment wants |
| Tears over a number line | Jumps too small or too many | Jump to the next ten first, then by tens |
| Area model answer is off | A box was left out or misread | Check that each box is row × column, then add all of them |
| Homework takes an hour in grade 3 | Load or skill gap | Compare with the 10-minute rule; tell the teacher |
Table: common Common Core homework problems and fixes.
If math homework regularly takes much longer than the 10-minutes-per-grade guideline, that is worth raising at the next conference. Our list of questions to ask at a parent-teacher conference includes math-specific ones.
Where to find more help
Start with the class materials, then free resources that use the same methods. Many districts post family guides for their math curriculum on the school website, often with videos for each unit. Ask the teacher which program your class uses; the publisher usually has free parent pages.
Beyond that:
- Our roundup of free homework help websites lists free tutoring and practice sites by subject.
- The math homework help guide has a free resource table by level, from elementary to college.
- If you are thinking about apps, our comparison of AI math solvers explains which ones show steps and how to use them without skipping the learning, and our guide to AI math help covers chatbots that explain well but sometimes get arithmetic wrong.
- If homework battles are about starting rather than understanding, the homework motivation tips and a shared homework planner help more than another explanation.
- For more on supporting schoolwork at home, see the parents’ hub.
When a worksheet still makes no sense, the answer key is not the most useful thing to look for. A note to the teacher that says “we tried the area model and got stuck at the second row” gets you help that matches exactly what your child is being taught.