1, do subtraction, want to add. Do the inverse of addition with subtraction and think with addition. For example, 12-8, Xiang 8+( )= 12. ?
2. Violation of the Ten Laws. For example, 13-7 can be thought as follows: 10-7+3=6.
3. Continuous subtraction (commonly used method), such as 13-7. You can think of it as' continuous subtraction ': 13-3-4 = 6, which means dividing 7 by 3 and 4.
4. Supplementary methods. For example, 13-7 can also be thought like this: 13- 10+3=6.
The method of "adding ten's complement" is to first turn meiosis into ten (we call this number that forms ten with meiosis the complement of meiosis), and then add the complement of meiosis to the number in the unit of meiosis. For example, to calculate 14-9, first make meiosis ten (9 and 1 make up ten), and "1" is the complement of 9; Then add the complement of the minuend (9) to the 4 in the (14) position, that is, 4+1= 5 "5" is the number of questions.
The contents and methods of first-grade mathematics;
Master the number within 100. Familiar with the composition of numbers within 10, the addition and subtraction of calendar elimination, and familiar with common geometric figures, such as squares, rectangles, triangles, circles, cubes, cuboids, cylindrical grinders, etc. Know the clock face and learn to compare the size and number of numbers. Know the RMB and learn to find the rules.
Create a harmonious classroom atmosphere and guide students to actively participate in learning. Happiness imitates the scene of the blind bridge shed, allowing students to enter the mathematics life. Interesting cooperation and interaction between teachers and students will make students feel the joy of learning mathematics, leave students with room for independent thinking, and give every student a chance to express himself. Create exercises closely related to life, so that students can learn to apply mathematics.