Is that a 5 digit phone number written in pen?
Discussion
Yep (pic is not from our phone - but we had the same model and same trendy pale yellow 70's style colouring).
All the numbers in our suburb where 4 or 5 digit.
Also had the big heavy physical printed paper phone books with everyone's address and number laying next to it 😄
We were at six digits when I was a kid with those rotary phones and prefixed 2 more digits by the time these button phones came along with a whopping 10 number programmable memory.
Still remember the old phone books, white pages for private and yellow pages for commercial..