Basic abacus as a manipulative

I didn't want to leave out one of the best manipulatives there is for grades 1-2: just a simple "school" abacus that has 10 wires and 10 beads on each wire.

I'm not talking about a Chinese or Japanese abacus with a special counting system.

I'm talking about just using this simple abacus for counting, and treating each bead as 1. You don't have to learn any of these sophisticated systems that have been in use with various abacuses. Just consider each bead being 1, period. Then you have essentially 10 tens, or a hundred, in your abacus.

And that goes a long way explaining tens and ones or 2-digit place value on 1st grade.

You can also show the child things such as similarities in
10 − 5
20 − 5
60 − 5

or let the student find sums of 2-digit numbers: 23 + 45. He can move 2 tens and 4 tens, then 3 and 5 individual pieces - so the abacus can model adding the tens and ones separately.

You can let the child explore what happens with 28 + 9.

It's better if the abacus has the first five beads colored differently from the next five, in each row, like in this silly picture.

Then the child will easily recognize 6, 7, and 8 beads without counting. Also, let's say you'd choose 6 beads on one wire and 8 on the next one. You can show how the five and five on those two wires makes ten, and some are left over.

You can also model multiplication: move for example 4 beads on each of the 5 neighboring wires and you have 5 times 4.

So this is not rocket science; it is very easy. No need to learn any new systems.

Here's a picture of an old school abacus.

Wikipedia has info on all different kinds of abaci, including this kind of usage of the school abacus.

You can browse Amazon's abacus selection here.