88880:110+х=809.
808+x=809
x=809-808
x=1
----------------------------------------------
6871+р:121=7000.
p:121=7000-6871
p:121=129
p=129*121
p=15609
-----------------------------------------
3810+1206:y=3877.
1206:y=3877- 3810
1206:y=67
y=1206:67
y=18
-------------------------------------
k+12705:121=105
k+105=105
k=105-105
k=0
-----------------------------------