Formula: plus 9 minus 1, plus 8 minus 2, plus 7 minus 3, plus 6 minus 4, plus 5 minus 6, plus 3 minus 7, plus 2 minus 8, plus/kloc-0 minus 9. (Note: The words added in the oral decision refer to the number in the unit. )

Example: 26+38=64 Solution: Add 8 and subtract 2. Who will subtract 2? 26 minus 2 equals 6. Three out of 38 will get four points.

(Note: How to round the last ten digits is 1, I enter 2, 2, 3, 4, and so on. Where are you taking it? It reaches the tenth place in the second two digits. If this is 3, I enter 4, and these two digits are 2+4=6. ) Here, 26+38=64 means that 6-2=4 is written with one digit, and 3 into 4 plus 2 means that 6 is written with ten digits.

Another example is 42+29=7 1. Just add 9 and subtract 1, 2- 1= 1, and write 1 in one place, which is 2. I enter 3,4+3 = 7, and write 7 in ten places to get 7 1.

If two numbers don't add up to carry, you can write the number directly, for example, 25+34=59, write one digit and one digit on the number after the equal sign, 5+4=9, and write ten digits and ten digits on the tenth digit, which is 2+3=5, which is 59. No vertical calculation is required.

2. Method 2: abdication subtraction of two digits minus two digits.

Oral decision: minus 9 plus 1, minus 8 plus 2, minus 7 plus 3, minus 6 plus 4, minus 5 plus 5, minus 4 plus 6, minus 3 plus 7, minus 2 plus 8, minus 1 plus 9. (Note: If you decide orally to reduce a few words, you will reduce single digits.)

Example: 73-46=27, solution: subtract 6 and add 4, who will add 4? Three plus four equals seven. Written in one place, the decimal place of subtraction is four. I will retire. Who will retire? 7 returns 5, which is 27.