Standard Algorithm

Definitionnoun phrase

What is the standard algorithm in math?

The standard algorithm is the usual written column method for adding, subtracting, multiplying or dividing multi-digit numbers. You line up digits by place value, work one place at a time, and regroup (carry or borrow) when a place overflows or runs short. For 478 + 365 it gives 843 in three short steps.

In Spanish
algoritmo estándar
Also called
traditional method, column method, carrying and borrowing
Grade level
K-5
Grade 4Grade 5Grade 6CCSS 4.NBT.B.4CCSS 5.NBT.B.5CCSS 6.NS.B.2TABEGED

Standard Algorithm in a picture

Standard addition algorithm for 478 plus 365Column addition of 478 and 365 with the digits lined up under hundreds, tens and ones. Small regrouped 1s sit above the tens and hundreds columns. The answer is 843. Steps: ones 8 plus 5 is 13, write 3 and regroup 1; tens 1 plus 7 plus 6 is 14, write 4 and regroup 1; hundreds 1 plus 4 plus 3 is 8.Standard algorithm for 478 + 36511478+365843HTOWork right to left, one place at a time:ones: 8 + 5 = 13 → write 3, regroup 1 tentens: 1 + 7 + 6 = 14 → write 4, regroup 1 hundredhundreds: 1 + 4 + 3 = 8 → write 8478 + 365 = 843
The standard algorithm adds one place at a time from right to left. Each regrouped 1 moves ten of a place into the next place.

Formal definition and notation

A computation algorithm is a fixed set of steps that, carried out correctly, always gives the right result. The standard algorithms for whole numbers process digits by place value: addition and subtraction from the ones place leftward with regrouping, multiplication by partial products of one digit at a time, and division by long division from the highest place down. The Common Core asks for fluency with them by grade 4 (addition and subtraction), 5 (multiplication) and 6 (division).

Key facts

  • Line up the ones digits, not the first digits, so every column has one place value.
  • Addition: when a column totals 10 or more, write the ones digit and regroup 1 into the next column (8 + 5 = 13).
  • Subtraction: when the top digit is too small, regroup 1 from the next place: 52 becomes 4 tens and 12 ones.
  • Multiplication: multiply by each digit of the bottom number, shifting one place left each time, then add the partial products.
  • Division: the standard algorithm is long division, which works from the left, not the right.
  • Other methods, such as the area model and partial quotients, show the same place-value ideas; the standard algorithm is the most compact.

Try it: place value behind the columns

Interactive

Each column of the standard algorithm is one place in this chart. Look at 843: 8 hundreds, 4 tens and 3 ones, the answer to 478 + 365.

This interactive needs JavaScript. The worked examples below show the same ideas step by step.

Standard Algorithm examples, step by step

Example 1: Subtract with regrouping

Warm-up

Use the standard algorithm to find 704 − 268.

  1. Ones: 4 is less than 8. The tens place is 0, so regroup from the hundreds: 704 becomes 6 hundreds, 9 tens, 14 ones.
  2. Ones: 14 − 8 = 6.
  3. Tens: 9 − 6 = 3.
  4. Hundreds: 6 − 2 = 4. Check: 436 + 268 = 704.

Answer: 704 − 268 = 436

Example 2: Multiply two-digit numbers

Core

Use the standard algorithm to find 47 × 36.

  1. Multiply by the ones digit 6: 47 × 6 = 282.
  2. Multiply by the tens digit 3 (really 30): 47 × 30 = 1,410. Write it shifted one place left.
  3. Add the partial products: 282 + 1,410 = 1,692.

Answer: 47 × 36 = 1,692

Example 3: Find the error

Test-style

Ana computed 356 + 87 and got 1,226. What went wrong, and what is the correct sum?

  1. Ana lined up 87 under the 35 instead of under the 56, so 87 was treated as 870.
  2. Line up the ones: 356 over 087.
  3. Ones: 6 + 7 = 13, write 3, regroup 1. Tens: 1 + 5 + 8 = 14, write 4, regroup 1. Hundreds: 1 + 3 = 4.

Answer: She misaligned the columns; the correct sum is 443.

Common mistakes

✗ MistakeAdding 68 + 57 and writing 1,115 (13 in the ones, 11 in the tens).
✓ InsteadRegroup: ones 8 + 7 = 15, write 5, carry 1; tens 1 + 6 + 5 = 12. The sum is 125.

Each place can hold only one digit; ten of a place becomes one of the next place.

✗ Mistake82 − 47 = 45, by taking 2 from 7.
✓ InsteadRegroup: 7 tens and 12 ones; 12 − 7 = 5, 7 − 4 = 3, so 35.

Always subtract the bottom digit from the top digit, regrouping when the top is smaller.

✗ MistakeIn 34 × 25, adding 170 and 68 to get 238.
✓ InsteadThe second partial product is 34 × 20 = 680, so 170 + 680 = 850.

The tens digit stands for tens, so its partial product is shifted one place left.

Not to be confused with

Standard Algorithmvs.Area model

The area model writes every partial product in its own box; the standard algorithm combines them in fewer written lines.

Standard Algorithmvs.Long division

Long division is the standard algorithm for division specifically. The term standard algorithm covers all four operations.

Quick check: 3 questions

Question 1 of 3

Using the standard algorithm, what is 5,009 − 1,375?

Show answer and explanation

Answer: B. Regroup across the zeros: 5,009 becomes 4 thousands, 9 hundreds, 10 tens, 9 ones, so 9 − 5 = 4, 10 − 7 = 3, 9 − 3 = 6, 4 − 1 = 3: 3,634. 4,374 takes the smaller digit from the larger in each column; the others slip one regrouping.

Question 2 of 3

In the standard algorithm for 63 × 48, what is the second partial product?

Show answer and explanation

Answer: C. The tens digit 4 means 40: 63 × 40 = 2,520. 504 is 63 × 8, the first partial product; 252 forgets the shift; 3,024 is the final product.

Question 3 of 3

When adding 5,678 + 2,456, how many times do you regroup?

Show answer and explanation

Answer: D. Ones: 8 + 6 = 14 (regroup). Tens: 1 + 7 + 5 = 13 (regroup). Hundreds: 1 + 6 + 4 = 11 (regroup). Thousands: 1 + 5 + 2 = 8. Three regroupings; the sum is 8,134.

Standard Algorithm: frequently asked questions

What does the standard algorithm mean in Common Core?

It means the familiar column methods: stack the numbers by place value and compute one place at a time with regrouping. Common Core expects students to add and subtract this way fluently in grade 4, multiply in grade 5 and divide in grade 6, after first learning strategies such as area models that explain why the steps work.

Is carrying the same as regrouping?

Yes. “Carrying” (in addition) and “borrowing” (in subtraction) are older names for regrouping. When the ones add to 13, you regroup 10 ones as 1 ten and carry it to the tens column. When you borrow, you break 1 ten into 10 ones. Teachers prefer “regroup” because it describes what really happens to the place values.

Practice and tools

Sources

  1. Common Core State Standards, Grade 4 Number and Operations in Base Ten (4.NBT.B.4)
  2. Common Core State Standards, Grade 5 Number and Operations in Base Ten (5.NBT.B.5)
  3. Common Core State Standards for Mathematics, Glossary (computation algorithm)
  4. OpenStax, Prealgebra 2e, 1.3 Subtract Whole Numbers

Updated November 2026·Reviewed by the Effortless Math team·Standards: CCSS 4.NBT.B.4, CCSS 5.NBT.B.5, CCSS 6.NS.B.2

Cite this entry

Effortless Math Team. “Standard Algorithm.” Effortless Math Dictionary. Updated November 2026. https://www.effortlessmath.com/math-dictionary/standard-algorithm/

Flashcard

TermStandard Algorithmline up, one place at a time, regroup
DefinitionThe column method for multi-digit arithmetic: line up place values, work one column at a time, regroup as needed. 478 + 365 = 843.
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