(1) Direct addition and direct reduction

1. Direct addition: Look at the beads outside, just add them directly.

Exercise: 2+2 3+ 1 2+ 1 5+3 3+5.

4+5 1+5 2+5 1+7 2+6

2. Key points of direct reduction: reducing inner beads is enough to reduce direct reduction.

Exercise: 4-2 4-3 6- 1 8-2 7-5

8-5 9-5 9-4 8-7 9-8

(2). Five plus five minus.

1. Full five plus essentials: if the foundation is not enough, add five and subtract five.

Exercise: 4+4 2+3 3+3 4+3

2. Break the five points: if the reduction is not enough, it will be reduced by five plus.

Exercise: 8-4 7-3 6-2 5-2

③ Carry plus abdication minus.

1. Carrying and adding essentials: if this file is full of ten, it will be reduced to one.

Exercise: 2+8 3+7 4+6 5+5

4+7 4+8 3+9 2+9

2. Main points of demotion: this file has not been reduced enough, so it will be refunded.

Exercise:11-712-811-510-5.

15-8 16-9 13-4 1 1-9

(4) Break quintile, abdicate more than five minus.

1. Break five and add essentials: If this document exceeds ten, add one and subtract five.

Exercise: 5+6 7+7 8+6 5+9

6+7 5+8 6+6 6+8

2. Deduct five points after abdication: this file is not reduced enough, and it is reduced by one plus five.

Exercise:12-613-813-711-6.

? 12-7 14-8 14-7 13-6