﻿Teacher Troy stands in front of a blackboard. A subtraction on the board reads 43 minus 19.

Teacher Troy is in his thirties, bald and with a shadow of a beard. He wears a blue Homework Help T-shirt.

He says HI
TVO KIDS.
THIS IS TEACHER
TROY HERE.
WE'RE GOING TO
SUBTRACTION IS
SOMETHING THAT
SOMETIMES IT'S
PRETTY EASY IF
YOU'RE SUBTRACTING
NUMBERS LIKE
YOU KNOW,
FIVE MINUS TWO,
THAT EQUALS
THREE.
BUT
SOMETIMES IT GETS,
SUBTRACTION CAN BE
A LITTLE BIT
MORE
DIFFICULT.
IT GETS A LITTLE
HARDER WHEN WE
SUBTRACTING DOUBLE
DIGIT NUMBERS.
AND AS WE REMEMBER
SUBTRACTING
DEALS
WITH TAKING AWAY.
SO RIGHT HERE
WE HAVE THE
NUMBERS
43 SUBTRACT 19.
NOW WHEN YOU'RE
DOING DOUBLE
DIGIT
SUBTRACTION
YOU ALWAYS HAVE
TO LOOK AT
OUR
PLACE VALUE.
SO OUR PLACE VALUE
FOR EXAMPLE
IS WE HAVE
THE ONES COLUMN AND
WE HAVE THE
TENS COLUMN.
SO IN THIS CASE
WE HAVE THREE,
SO THERE'S
THREE ONES,
AND FOUR
GROUPS OF TEN
WHICH IS
FORTY.
SO WHEN WE'RE
DOING OUR SUBTRACTION
AND WE LOOK
AT IT,
THERE'S
A PROBLEM.
THREE SUBTRACT NINE,
YOU CAN'T
DO IT BECAUSE
NINE IS LARGER
THAN THREE.
SO WE HAVE TO GET
INTO SOMETHING
THAT'S
CALLED BORROWING.
WE ALWAYS DO THAT,
WE BORROW
SOMETHING
FROM OUR FRIEND.
YOU DON'T HAVE AN
ERASER IN
CLASS YOU
BORROW IT TO HELP
YOU DO YOUR
WORK.
SO FOR
EXAMPLE HERE,
THE ONES ARE GOING
TO BORROW FROM
OUR TENS.
SO THIS 40
NOW, WE'RE GOING
TO CROSS IT
OUT,
WE'RE GOING
TO DRAW THREE.
AND THAT THREE
NOW WILL
REPRESENT 30,
10 TO IT SO
THAT 10 NOW,
IS 10 PLUS
THREE WHICH IS 13.
13 IS LARGER THAN
NINE, SO WE CAN
DO THE
SUBTRACTION,
13 SUBTRACT 9
GIVES US A 4.
AND NOW,
BECAUSE IT'S NOT
A 40 ANYMORE, IT'S
NOW A 30,
THE THREE
SUBTRACT THE ONE
EQUALS TWO, AND
THAT TWO
REPRESENTS 20.
SO OUR RESPONSE,
SO WHENEVER YOU'RE
DOING BORROWING
YOU JUST
LOOK AT THE ONES,
YOU LOOK AT
THE NUMBERS.
THE NUMBER APPEAR
SMALLER THAN
THE NUMBER
BELOW, YOU HAVE TO
BORROW THE 10 TO
MAKE IT WORK,
AND GO
FROM THERE.
I'M TEACHER TROY AND
I HOPE THAT HELPS.