okay today what we're gonna be doing is
working with one of our second-grade
students and showing how to use
subtraction on the number line and the
best thing about this is that we can get
around using what we used to call
borrowing so if you notice the six which
is in the ones place is a smaller number
than the eight normally in the old way
of doing it we would have to cross out
numbers borrow from the tens and so on
and so forth we can get around this by
using our number line and our student
here is going to show us how so which
number are we going to start with on the
number line very good so let's write 38
on the number line because that's the
number that we are subtracting from 76
so what is our bigger number and which
one is gonna go in it good job okay now
what we want to do next is simply we're
gonna try and figure out I always tell
the students how much stuff is in the
middle how much area is in between these
numbers and that's essentially what
subtraction is so our student is going
to show us how we can do that now
remember from the last video we talked
about we can do jumps of 20 sometimes or
10 or even one and sometimes even five
to try to get to that goal number of 76
so which number which skip jump would
you like to start with I'm gonna do a
skip jump of plus 20 you can see he's
recording that he went from 38 plus 20
did you get to 58 great now are we at 76
yet nope we still have a little ways to
go so what would you like to do next
skip jump of 10 there great that puts us
at 68 you'll notice we're not at 76 yet
but we're gonna keep working towards
that and there's not really enough room
to go another 10 so what would you like
to do next skip jump of 5 would work
great there so 68 plus 5
very good 68 plus 5 is 74 you notice
he's keeping his numbers on the bottom
organized so that he's not loose so he's
not losing his place and he's keeping
his number line as a as organized as
possible so let's put 73 down there now
do we have any room for any more skip
jumps of 5 so we're gonna have to go
with ones right so 73 plus one is 74
plus another one it's going to put us
add what number we slip one more to go
so let's do one more skip jump of one
you have some room there and when we go
one skip jump of one that's gonna put us
at our goal of 76 which is the number
you wanted to get to so now we've got
the hard part out of the way and now we
want to see what the actual difference
is and this is where it gets really cool
now we just have to add up all of these
numbers in between here and we should
get the difference between 76 and 38 so
we simply we have a 20 here millon
what's 20 plus 10 okay so that puts us
that 30 got rid of that 10 30 plus 5 25
35 and now we have these ones to get rid
of so 35 plus 1 equals 36
so our final answer is going to be 38
so 76 - 38 should put us at the number
