Abacus Lesson 26 // Subtraction-Complementary Numbers Respect to 10- TEN'S Column Video Lecture | Abacus Master Class:Become an Expert (English) - Personal Learning

all right lesson 26 learning the abacus
and we are doing subtraction in the tens
column with respect to the number ten so
here we go subtraction clear your abacus
and we are going to start with 43 minus
19 now if you went through the last
problems this is going to be a piece of
cake and it's fun
adding on little piece by little piece
so here we go let's put the number 40 Oh
what are we going on 43 on the abacus
there's the number 43 and we are going
to subtract or take from that the number
19 and the same thing with addition as
we did in this the addition part of this
is we start on the left hand side of it
and work our way that direction and
that's different from other types of
math your standard textbook math is is
different but this is how we do in
abacus world and so we're going to start
here and we're going to take from it 19
that means that we start with the number
1 in the tens column because when you
look at the number 19 there's a 1 and a
nine and so we are going to start here
in the tens column and just take one
beat away there in the tens column that
part is done and now we need to take 9
away from the ones column and as you
look at that and stare at it and think
about a little bit and you say you know
I don't know that we can do this because
there's not 9 beads in the ones column
that we can use that's when we know we
need to use complementary numbers and
when we're subtracting we add the
complement and in this case it's 1 1 is
the complement to the number 9 there we
go and we subtract 1 from the next
column over so there it is 43 my
19 is a 2 and a 4 24 43 minus 19 is 24
all right let's do another one
that was fun let's do 22 minus 8 all
right
22 there is the number 22 and we're
going to subtract from that the number 8
well the number 8 has a 0 in the tens
column so we don't do anything here but
it does have an eight in the ones column
so here we go we go and we look at that
and say hmm I think we need to use
complementary numbers here because
there's not enough well since we're
subtracting we add the complement and
the complement over the number eight is
a you got it the number two and we
subtract one from the tens column and
there it is 22 minus eight is a 1 and a
4 14 22 minus 8 is 14 all right let's do
one with two-digit numbers and both of
those are fun let's do 71 minus 19 so we
put 7 and a 1 here 71 minus 19 all right
so we start here in the tens column work
in that direction remember and a 19 is a
1 and a 9 so that means I take away 1
here and I take away 9 here oh look at
that there's not enough beads so we use
complementary numbers the complement to
the number 9 is a 1 so I'm going to add
the complement and take away a bead in
the tens column so 71 minus 19 is a 5
and a 252 71 minus 19 is 52
all right here we go let's do a couple
more of these let's try 93 minus 35 so
let's put a nine here and a 3 here
there's the number 93 and we are going
to subtract from that 35 so we start
over here our 35 is written a 3 and a 5
I take away 3 from the tens column and I
go to take away 5 here oh how am I going
to do that oh complementary numbers
there we go so I add the complement and
take away 1 here there it is 93 minus 35
is a 5 and an 8 58 93 minus 35 is 58 all
right we'll do one more and I think you
will have this clear your abacus all
right let's try this one let's do a
bigger number like 156 minus 98 so let's
put the nut I know we're kind of getting
ahead of ourselves but it's fun to end
with a big number so put the number 156
on your abacus a 1 in the hundreds
column a 5 in the tens column and a six
in the ones column there's the number
156 and we are going to take from that
or subtract from that the number 98 now
the number 98 has a 0 in the hundreds
column so we don't need to do anything
there and we start here in the tens
column so we go to take 9 from that not
enough beads so that means we add the
complement the complement to the number
9 is a 1 and then we take this away in
the hundreds column and we move on to
the ones column there's an 8
we need to take away there well there's
hmm okay I see we don't have enough we
got to use our complementary numbers
since we're subtracting we add the
complement and take away one from the
next column over so there it is 156
minus 98 equals a five and an 858 is the
answer to that now I'm just guessing I
might be totally off on this but I think
we're starting to finally stretch your
brain this might be a little bit
difficult or might not you might be able
is this just coming naturally but just
wanted to remind you if you get to the
point where you're going through the
worksheet and you just can't remember
quite what you're supposed to do come
back and watch this video again and see
if it answers your question
and when you're done we're moving on to
the next section
you