 The next algorithm that we are going to
be working with is the trade first method and the trade first method is a lot like
continuing with the borrowing process and subtracting we are going to get all of our borrowing done first and then we are going to do the
subtracting at the end. So let’s see what I’m talking about. So to understand the trade first method
we’re going to first look at the ones column and when we look at the ones column like the
traditional method we’re looking to see if this bottom number is bigger than
this top number and in this problem it is we have a
four at the bottom and a three at the top. So in order to subtract we’re going to
need to go next door and we’re going to make this a three and then we’re going to bring that one over in front of the three to have
thirteen. Now with the traditional method we would usually stop right now and
subtract thirteen from four, but with the trade first method we’re going to
continue in making sure we can actually start subtracting without having to do any more borrowing, but what we find out when we look in the
tens column is we have a five at the bottom and a three at the top so we’re
still going to need to borrow. So we’re going to borrow one from this nine and we’re going to have an eight and then we’re going to bring that one over in front of the three so we’ll have
a thirteen and now we have eight take away six in
the hundreds column which we can do so now we’re going to go all the way back to
the ones column and do all of our subtracting. So we have thirteen take away four which
is nine and we have thirteen take away five
which is eight and then we have eight take away six which is two and we end up with the answer of two
hundred eighty-nine. This next problem we are also going to
column and we’re going to look at the bottom number to see if it is bigger
than the top number and in this situation it is so in order to subtract we are going to
need to move next door to the tens column. We are going to borrow one from this one and it will become a zero and this one will become an eleven and then remember since we’re doing the trade
first method we are not going to start subtracting now we’re going to keep
looking at the problem to see if we need to borrow any more. So we’re going to look at the tens column the three is bigger than the zero so we are going to need to borrow from
this one we’re going to cross it off make it a zero. We’re going to take that one that we
borrowed and we’re going to move it over here next to this zero so now we have ten and now let’s look at the hundreds
column. The three is bigger than a zero so we’re
going to need to borrow from this three make it a two and then move that one over in front of the
zero to have another ten so now we can subtract two from two so now we’re going to go ahead and
subtract this problem. So we’re starting back at the ones column we
have eleven take away two which is nine and then in the tens column we have ten take
away three which is seven and in the hundreds column we ten take away three which is also
seven and we have two take away two which is
zero and remember we do not need to put a zero if it is the first number in the answer. So that is how you use the trade first
method.

1. Tay says:
2. AngelicBeatdown says:
3. Jason Ashby says: