Multiply 23 by 47 using two partial products: one for the ones digit of 47 and one for the tens digit. Each partial is computed digit by digit; then the two partials are added to give the final product.

Example

Multiply 23 by 47 with shifted partial products.

highlighted = computed this step

Step 1 — Set up

Set up the multiplication board.

xxx23×xx47xxxxx\begin{array}{rrrrr}\phantom{x}&\phantom{x}&\phantom{x}&2&3\\\times&\phantom{x}&\phantom{x}&4&7\\\hline\\\phantom{x}&\phantom{x}&\square&\square&\square\\\phantom{x}&\phantom{x}&\square&\square&\square\\\hline\\\phantom{x}&\square&\square&\square&\square\end{array}
Set up 23 x 47aligned partials----23x----47------------------------ones row, shifted tens row, then sumones row: x 77 x 3 = 21, write 1 and carry 27 x 2 tens + carry 2 = 16 tens; row 161tens row: x 4 tens4 x 3 = 12, write 2 and carry 14 x 2 tens + carry 1 = 9 tensraw 92, shift one place to 920add aligned partials-- + -- = --

Step 2 — Ones partial

Ones digit 7: 3 x 7 = 21, write 1, carry 2; partial 161.

xxx2xxxx23×xx47xx161xxx\begin{array}{rrrrr}\phantom{x}&\phantom{x}&\phantom{x}&\hl{2}&\phantom{x}\\\phantom{x}&\phantom{x}&\phantom{x}&2&3\\\times&\phantom{x}&\phantom{x}&4&7\\\hline\\\phantom{x}&\phantom{x}&\hl{1}&\hl{6}&\hl{1}\\\phantom{x}&\phantom{x}&\square&\square&\square\\\hline\\\phantom{x}&\square&\square&\square&\square\end{array}
7 x 3 = 21: write 1, carry 2aligned partials2carry----23x----47--161----------------ones row, shifted tens row, then sumones row: x 77 x 3 = 21, write 1 and carry 27 x 2 tens + carry 2 = 16 tens; row 161tens row: x 4 tens4 x 3 = 12, write 2 and carry 14 x 2 tens + carry 1 = 9 tensraw 92, shift one place to 920add aligned partials-- + -- = --

Step 3 — Tens partial

Tens digit 4: 3 x 4 = 12, write 2, carry 1; shift partial to 920.

xxx1xxxx23×xx47xx161xx920x\begin{array}{rrrrr}\phantom{x}&\phantom{x}&\phantom{x}&\hl{1}&\phantom{x}\\\phantom{x}&\phantom{x}&\phantom{x}&2&3\\\times&\phantom{x}&\phantom{x}&4&7\\\hline\\\phantom{x}&\phantom{x}&1&6&1\\\phantom{x}&\phantom{x}&\hl{9}&\hl{2}&\hl{0}\\\hline\\\phantom{x}&\square&\square&\square&\square\end{array}
4 tens x 23 gives 920aligned partials1carry----23x----47--161--920--------ones row, shifted tens row, then sumones row: x 77 x 3 = 21, write 1 and carry 27 x 2 tens + carry 2 = 16 tens; row 161tens row: x 4 tens4 x 3 = 12, write 2 and carry 14 x 2 tens + carry 1 = 9 tensraw 92, shift one place to 920add aligned partials-- + -- = --

Step 4 — Add partials

Add partials: 161 + 920 = 1081.

xxx23×xx47xx161xx920x1081\begin{array}{rrrrr}\phantom{x}&\phantom{x}&\phantom{x}&2&3\\\times&\phantom{x}&\phantom{x}&4&7\\\hline\\\phantom{x}&\phantom{x}&1&6&1\\\phantom{x}&\phantom{x}&9&2&0\\\hline\\\phantom{x}&\hl{1}&\hl{0}&\hl{8}&\hl{1}\end{array}
161 + 920 = 1081aligned partials----23x----47--161--9201081ones row, shifted tens row, then sumones row: x 77 x 3 = 21, write 1 and carry 27 x 2 tens + carry 2 = 16 tens; row 161tens row: x 4 tens4 x 3 = 12, write 2 and carry 14 x 2 tens + carry 1 = 9 tensraw 92, shift one place to 920add aligned partials161 + 920 = 1081

Step 5 — Result

Read the complete product: 1081.

xxx23×xx47xx161xx920x1081\begin{array}{rrrrr}\phantom{x}&\phantom{x}&\phantom{x}&2&3\\\times&\phantom{x}&\phantom{x}&4&7\\\hline\\\phantom{x}&\phantom{x}&1&6&1\\\phantom{x}&\phantom{x}&9&2&0\\\hline\\\phantom{x}&1&0&8&1\end{array}
23 x 47 = 1081aligned partials----23x----47--161--9201081ones row, shifted tens row, then sumones row: x 77 x 3 = 21, write 1 and carry 27 x 2 tens + carry 2 = 16 tens; row 161tens row: x 4 tens4 x 3 = 12, write 2 and carry 14 x 2 tens + carry 1 = 9 tensraw 92, shift one place to 920add aligned partials161 + 920 = 1081
partial-product Each digit of the multiplier generates its own partial product, which is shifted left by the digit's place value before adding.
two-pass-multiplication The standard long-multiplication algorithm works one multiplier digit at a time, building one partial product per digit.