Question

[(420+2•40):(4•25)+15•5]:(4•2)+15•6=100•b

Answer 1

[(420+2•40):(4•25)+15•5]:(4•2)+15•6=

=[(420+80):100+75]:8+90=

=(500:100+75):8+90=

=(5+75):8+90=

=80:8+90=

=10+90=

=100