Systematic Treatise on Arithmetic

Level: Four times five gives twenty; change five to two.
Two enters At its own position, remove the original
Four enters At the position below, add to the dividend

Start

Call the hundreds, then combine
The desired number arrives and is obtained
Restoration: Use the Four-Return Method original: 四歸 (sì guī); a specific abacus mnemonic for dividing a number by four. The method is detailed later.

Division by Four Table

One into four: twenty-two 10 divided by 4 equals 2 with a remainder of 2; on the abacus, this means placing a 2 in the current column and a 2 in the next.
Two into four: becomes five 20 divided by 4 equals 5.
Three into four: seventy-two 30 divided by 4 equals 7 with a remainder of 2.
When meeting four, advance ten.
When meeting eight, advance twenty.

Suppose there is currently a quantity of grain totaling 246 shi A unit of dry volume, often translated as a "stone" or "picul," roughly 100 liters. and 9 dou A "peck," equal to 1/10th of a shi.. For every shi, 5 dou of rice is milled.
Question: How much white rice should this yield?

The method states: Set the amount of grain as the Dividend original: 實 (shí) and use the 5 dou of milled rice per shi as the Multiplier original: 法 (fǎ). Multiply them together to reach the answer.

Method

Multiply