1, whose sum is 10 can be added first, such as 3 and 7, 2 and 8, or 1, 4 and 5 can be added first to calculate.

2, continuous subtraction, such as: 95-28=? Subtract the number of the same part as the minuend (i.e. 1 unit is the minuend and 10 unit is the minuend), and then subtract the number of the subtracted part. Process: First use 95-25=70. Then use 70-3=67.

3. subtract first and then add. Such as: 76-38=? You can subtract the minus 38 from the integer 70, and then use this difference to add the digits of the minus.