Academy of Math Subtraction – Level 8 Guided Notes Part 1 – In this activity you will be working with the concept of _______________________. Subtraction is a mathematical way of finding the ____________________ between two numbers. Subtraction is a way to find out how much one number is _______________ than, or less than another number. Part 2 – The top number is called the __________________. It is the number you ____________________ from. The next number is called the subtrahend. It is the amount you are ___________________ from the minuend. Changing the order of the numbers will change the difference. 25 minus 15 equals 10, but 15 minus 25 equals a difference less than _________ because you took away more than started with. The _______________ of the numbers in a subtraction problem will also ________________ the difference. (45 – 25) – 4 is _______ the same as 45 – (25 – 4). 1
So how do you know which one is the correct answer? The use of ___________________ tells you which operation to do first. It is also important to correctly line up the numbers to be ________________. If the numbers are not lined up correctly, the _________________ will be incorrect. Sometimes it is not necessary to find the exact difference. An ___________________ difference will give you an idea of the __________________ between two numbers. Round these numbers to the nearest ___________________ to find the __________________ difference. The estimated difference is _____, ________. Part 3 – Finding the _______________________ difference will give you a quick idea of what the ______________________ difference should be. _______________________ is an important strategy in solving subtraction problems. First _______________ the ones. The top number does not have __________________ ones. You can’t take ____ ones away from 3 ones. Next subtract the tens. Borrow one hundred or “ten tens” from the hundreds column and add it to the tens. Now there is _____ hundred and _____ tens. 2
Now subtract the _____________________. Then subtract the _____________________. Do you have to regroup to subtract the thousands? __________ (yes or no) Next subtract the _____________________. Borrow one hundred‐thousand to give you enough ten‐thousands to subtract. 17 ten‐thousands minus _____ ten‐thousands = _____ ten‐thousands. Finally subtract the ___________________________. So: 381,263 minus _____________ equals 188, 085. Part 4 – When subtracting _________________ you must remember to convert the subtraction problem into an addition problem by using the __________________ integer of the subtrahend. To find the answer of the subtraction problem (‐8) – (+6) find the _____________ integer of the subtrahend. 3
(+6) is the subtrahend so (_____) is its opposite. Then change the subtraction problem into an __________________ problem. (‐8) – (+6) is equal to (‐8) + (‐6). Now you can _____________ the problem. Using a number line find (‐8). This is the starting point. (_____) tells you to move 6 units to the _____________. (‐8) + (‐6) = (_____) so (‐8) – (+6) = (_____). First find the opposite integer of the subtrahend. In this example the opposite of (‐3) is (_____). Then change the subtraction problem into an addition: (‐5) ______ (+3). Now add. Starting at (‐5) on the number line, move ______ units to the ___________. (‐5) ______ (‐3) = (_____). Subtracting integers may seem confusing, but with _________________ it will get easier. Just remember to convert the subtraction problem into an ___________________ problem by using the ____________________ integer of the _______________________. 4
Academy of Math Subtraction – Terms 8 WORD BANK are subtracting difference zero ten‐thousands estimated 15 +6 left opposite ‐ greater 62.000 estimated taking away Regrouping hundred‐
thousands 8 solve opposite right +3 Part One Words subtraction Part Two Words brackets minuend not Part Three Words Yes 9 difference difference subtracted estimated hundreds 193, 178 affect thousand grouping 8 calculated enough thousands Part Four Words ‐14 integers ‐14 1 opposite ‐6 3 ‐2 subtract addition subtrahend + practice 5