| | | | | | - ＝ ÷ | ＝ | | a-x=b a÷x=b | | | | a-x=b a÷x=b | a | a | | | | | | - ＝ | ÷ = | | | | | - ＝ ÷ = | | | 1 ＝ - | | 20-x=8 | x=20-8 | x=12 | 2 ＝ ÷ | | 20÷x=4 | x=20÷4 | x=5 | | | | | 0 | | a-x=b a÷x=b | | | x x | | | | 1. | | | | 1 | 20-x=8 | 20-x+x=8+x | 20=8+x | 8+x=20 | 8+x-8=20-8 | x=12 | 2 | 20÷x=4 | 20÷x x=4 x | 20=4x | 4x=20 | 4x÷4=20÷4 | x=5 | 2. a-x=b 0 | a-x=b 1 | | | 1 | 20-x=8 | 20-x-8=8-8 | 12-x=0 0 | x＝12 | 2 | 4x÷x=4 | 20÷x÷4=4÷4 | 5÷x=1 1 | x＝5 | | | | | | | | | | | | 2021 2 | | |