Negative nine plus one, eight plus two, seven plus three, six plus four, five plus five, four plus six, three plus seven, two plus eight.

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Decimal method: a method of calculation. When the number of units is not enough, subtract the subtraction with 10 and add the remainder to the number of units, that is, the decimal method, for example, 1 1-3, and say, "1-3 is not enough, and there are two left, so we will start with 65438+.

The calculation of the method of breaking ten is based on the meaning of subtraction. Students can intuitively understand arithmetic through operation activities and form algorithms. The process of thinking is complicated, and students need to think in at least two steps-reducing first and then adding. Compared with counting and addition and subtraction, it is more difficult to understand, mainly because of students' existing counting habits.

References:

Lecture 8 Breaking Ten Methods in Computing Micro-Classroom-Education-HD Video-Iqiyi