# Using an Abacus with a Child Who Is Deafblind

These videos demonstrate the use of an abacus to solve addition and subtraction problems with a 4th grade student who is deafblind with an interpreter using tactile sign, braille, and a teacher.

Liam (4th grade, braille reader, deafblind) is proficient at adding and subtracting using base ten blocks.  Recently we (his team at school and I) have been working on him becoming proficient at adding and subtracting using the abacus.  Prior to learning how to add and subtract on the abacus he had instruction on how to set up numbers on the abacus and could do so independently and accurately.  We used the examples in the text, "Abacus Basic Competency: A Counting Method," by Susan M. Millaway to guide our instruction.  We are teaching the "Counting Method" in the videos.  (A simple definition of the Counting Method is that you count up [add] or countdown [subtract] one number at a time on the abacus).  We often will pair these lessons with the base ten blocks and writing his answers on the brailler.  He uses the abacus to check his work.

## Addition on the Abacus

In this video Liam adds 44 + 13 using the abacus. (Turn on closed captions.)

### Transcript:  Addition on Abacus

Teacher:  Okay, Liam, we're going to be doing an adding problem first on your abacus. Can you tell me the first number?

Liami (through interpreter): I erased the answer.

Teacher:  Can you tell me the first number there we're going to adding?

Liam (through interpreter): 44 add 13.

Teacher:  Okay, can you wait? Can you please set up the number 44?  Can you can you clear that for me?  What do we start with first?  What do we have to set up first: the tens or the ones? Did you set up the tens first?

Liam (through interpreter): No.

Teacher:  Okay, this time set it up, please. Tens first.  Four 10s.  And now 4 ones.  Alright, good.   So, now what are we going to add on the abacus?

Liam (through interpreter): 13

Teacher:  So how many tens do we need to add on to our 44?  Good job!  Okay, so I noticed that you started to put the 5 down for the  five 10s.  That was right.   That was good thinking.  So go ahead and put that 5 down, but then you need to clear the 4.  Good work!  And now you need to add how many ones?   Yeah, go ahead.   Good!  One.  Yep, 2 & 3.  Finished. Good job!  What is your answer then?

Liam (through interpreter):  57

Teacher:  Good work! Yes.

## Subtraction on the Abacus

In this video Liam is subtracting 137-13.  (Turn on closed captions.)

### Transcript:  Subtraction on Abacus

Teacher:  Can you read that problem for me, Liam?

Liam (through interpreter):  One hundred thirty-seven (137).

Teacher:  Okay, when you set up... you are right! You're going to set up the hundreds first. 100, good. 100 good.  Next?  Three tens. Good!  And then you've got the seven ones.  Good work, Liam! So, what are we going to be subtracting?  Can you read that?

Liam (through interpreter):  13.

Teacher:  13 is correct. So take away one 10.  You were right.  Okay and now let's take away three ones. Are you ready? I'll help. One. Okay, can you... let's start over because you went too fast for me. I think you are right, but let's go a little... let's do it together.   Start over. 137. 137.   Got it.  All right.  Let's take it away with me.   Are you ready?  So we've got to take away one ten and three ones.  Ready?  One, two, three.  There we go. I only needed to take away three, remember? So, what's your answer?

Liam (through interpreter): 124.

Teacher:  Perfect!  Good work, Liam.

Liam (through interpreter): Finished.

Posted on October 19, 2018
Updated on: October 26, 2018