This is the finished product. It's my cell phone number, which is obvious upon inspection, but just looks like any beaded bracelet from a distance. It doesn't give any would-be attackers information to use to convince my daughter to go with them, but it does give someone a way to contact me if needed. I made a bracelet, but you could adapt it to hang from a ribbon you pin to clothing, too.
Our local craft stores didn't have beads with numbers when I was looking. I ended up with an alphabet and number mega-assortment from Walmart. Which I have dumped out on my floor at least three times so far. I didn't get around to looking online, so I'm not sure if you can buy just what you need or have to go to the risk of spilling 988 little plastic beads that will take up permanent residence between the wall and some obscenely heavy piece of furniture. (The two separator beads came from a different unwise purchase...)
After you obtain your beads and locate all the numbers of your phone number, string them on an elastic thread (or ribbon) thin enough to fit the smallest bead opening. (I wasn't risking a fourth spill to get more decorative options.) Leave enough length to tie the elastic - I left about six inches extra because the elastic is challenging to work with.
The knot I used is called the Shake Hands Bend and I picked it because the tied ends come back out parallel to the main lines, instead of sticking out perpendicular. It's also symmetric, making it pretty. Although claimed to be easy to untie, after 'fairing' the knot, or pulling it tight, I wasn't able to undo it and it didn't come out even after clipping the tails short and pulling pretty hard on it. You're welcome to use any knot you choose, but if you don't have a favorite (or a clue, like me) this one seems to work pretty well.
It took me awhile to figure this knot out and the elastic was unruly, so I took to anchoring the ends after getting the over and under and arounds for each step. The bottom lines are the main lines that will have the beads on them and the tie ends you'll eventually cut off pointing up between them.
Coming from the right main line, make a loop down and go over the top of the main line (and under the Post-It notes). From the left main line, go under the right loop and out over the top, looping down. Make the full intertwined loop by taking the left tail end under the left main line.
Squiggle them together. Just kidding. Leave the left loop anchored and work with the right tail end. I'll confess to breaking out tweezers here. Take the right tail end that was pointing up and loop it down, first going under the right main line, then under the left main line, and up where the two loops intersect, over both lines.
This step makes the loops symmetric. Work with the left tie end (the right tie end is at the left side of this picture, not under Post-It notes) which was under the left main line and go over the right and left lines, in through the intersecting loops (where the right tie end came up through) and under the right and left loops.
If everything is the right place, when you start tightening the knot you'll see these two loops form. If not, it'll either pop apart or get lopsided. You can undo it and try again (or try another knot) at this point, but probably not after tightening all the way. If you need to adjust the bracelet length, maneuver the loops so the main lines first cross where you want the knot and pull the tail ends to tighten. Pulling equally on all four lines may make the bracelet too loose.
Your knot should look like this just before being secured. It does look pretty, for a knot, no? After tightening, clip off the tail ends. I snipped flush with the knot, but because the ends won't poke, you can leave them longer, if you want.
You can have your child wear this all the time, just in case, or only for outings like field trips, or anywhere in between. Since it's (relatively) easy to make, you can redo it out for new colors, a changed number, or a bigger size whenever you want.