Method 1: subtract 10 from 15, but at this time 2 1 13 is less than 526 1 15-9 1, so add 1, that is.

Method 2: 4 102: First, 15 minus 5 equals 10, but 1653 is less than 15-9 by 4, so we need to subtract 4, that is,15-5-.

"15 can be divided into the following categories? And "10" means 15=5+ 10, and put 5 in the box.

"10 with 9" means 10-9= 1, and 1 should be filled in the box below the connection.

Box (5) is followed by box (1), which means 5+ 1=6, and the total result is 6.

This question mainly examines "breaking the ten laws".

Analysis of "Breaking Ten Methods" Pictures;

Extended data:

Subtraction is a mathematical operation that represents the operation of removing an object from a collection. Subtraction follows several important patterns. It is anti-commutative, which means that changing the order will change the sign of the answer.

It is not associative law, that is, when a subtraction exceeds two numbers, the order of subtraction is very important. Subtracting 0 does not change a number. Subtraction also follows predictable rules related to addition and multiplication. These laws can be proved, starting with the subtraction of integers and summarizing them with real numbers and other things.