x:256=15
x=15×256
x=3.840
203*x=203
x=203:203
x=1
2×X=408
x=408:2
x=204
6459+x=9823
x=9823-6459
x=3.364
(x-128)-676=1835
x-128=1835+676
x-128=2.511
x=2.511+128
x=2.639
x:2:14+(64+36):10=17
x:2:14+100:10=17
x:2:14+10=17
x:2:14=17-10
x:2:14=7
x:2=7×14
x:2=98
x=98×2
x=196
2.280:x-40:2=40
2.280:x-20=40
2.280:x=40+20
2.280:x=60
x=2.280:60
x=38