2. subtraction: remember large numbers in your mind and count down decimals, for example, 6-3= remember 6 in your mind, count down 3, 5, 4, 3, and then get the result 6-3=3.
1, 1 1-20 numbers can be used to play guessing games with children. Describe numbers in three ways:
1) bit is 2, and the tenth bit is 1.
2) 1 ten, five one.
3) greater than 1 1 and less than 13.
Describe the numbers in these ways and let the children guess, or vice versa, until they are proficient.
2. Dial the number with the counter. Parents say the number and children dial the number. A composition that is said while dialing. For example, 12 consists of 1 tens and 2 ones.
In the mathematics teaching of senior one, carry addition and abdication subtraction within 20 are both the focus and the difficulty of teaching. General children learn the addition and subtraction within 10 in preschool. After entering primary school, they can master the addition and subtraction within 20 with a little practice, without carrying or abdicating. However, it is not so easy for children to learn carry addition and abdication subtraction. The calculation speed and accuracy of some students have decreased greatly, and polarization has begun to appear. Some students began to drag their homework because they couldn't keep up with the calculation speed, which became a difficulty for math learners.