DIY how to create a 5ft sized number 1 using foam boards

We will be creating a 5ft tall number 1 out of foam board.
You will need :
6 foam boards
stainless steel blade( or anything to be able to cut the foam boards)
clear duck tape
hot glue gun (xtra sticks)

Once I finished the number I wasn’t able to record myself filling it in with balloons I’m sorry.:( that will be a video for another time.