elementary-math Module
Interactive Simulation Screen
SYS_OK
Lesson Directive // Long MultiplicationREF_CORE

Multiply Each Digit

aa×\timesbb

Hover over a variable in the formula above, or see glossary below:

aa
Multiplicand
Whole Number
bb
Multiplier
Whole Number

Start from the rightmost digit of the multiplier. Multiply it by each digit of the multiplicand, right to left, carrying any tens digit.

INSIGHT: Multiplication is repeated addition — 4 × 3 means 4 added together 3 times.

Shift & Add Partial Products

For each digit in the multiplier, write the partial product on a new row, shifted one place to the left. Then add all partial products together.

INSIGHT: Each digit position represents a power of 10 — that is why you shift left.
Detailed Theory & ReferencesEXT_DOC

Long Multiplication

Long multiplication is a method of multiplying two numbers by breaking the problem into smaller, simpler steps using the distributive property of multiplication.

The Distributive Property

Every multi-digit number can be broken into its place values: 24×13=24×(10+3)=(24×10)+(24×3)24 \times 13 = 24 \times (10 + 3) = (24 \times 10) + (24 \times 3)

Standard Algorithm

  1. Write the two numbers vertically, larger on top.
  2. Multiply the top number by the ones digit of the bottom — this is the first partial product.
  3. Multiply the top number by the tens digit of the bottom, placing a zero placeholder in the ones column — this is the second partial product.
  4. Add the partial products together.

Carrying

When a multiplication produces a two-digit result (e.g. 7×8=567 \times 8 = 56), write down the ones digit and carry the tens digit to the next column to be added.

References

AI NOTICE

AI Assistance Disclaimer: This module uses AI-assisted educational models and interactive visual representations to help explain scientific and mathematical concepts. For formal research or academic evaluation, please verify formulas and data against standard primary reference materials.