245678765432+86x-23546432:4x=
$${\mathtt{245\,678\,765\,432}}{\mathtt{\,-\,}}{\mathtt{23\,546\,432}} = {\mathtt{245\,655\,219\,000}}$$
245655219000+86x:4x
$${\frac{{\mathtt{245\,655\,219\,000}}}{{\mathtt{2}}}} = {\mathtt{122\,827\,609\,500}}$$
122827609500+43x:2x
And that is it!