• 3 months ago
Transcript
00:00Hello, guys. I am in outer space with Mr. Robot, and I could use your help. While on
00:07my way back from Jupiter, I did not pay attention to my energy gauge. My ship is low on energy,
00:15and I could use a boost. This ship takes math fuel, and the fuel I need today is subtraction
00:20fuel. Can you help me? Great, let's get some fuel. In order to get the right fuel,
00:29we need to not just do subtraction problems, but understand subtraction as an unknown add-end
00:34problem. If you don't know what that means, don't worry. We will get there. Here is
00:41a group of circles to help us understand subtraction and addition. Let's separate these circles
00:46into two groups. On the left is a group of six, and on the right is a group of four.
00:55If we add the group of six and the group of four, we will get ten, because that is
00:59what we started with. What's awesome about this is that we can also switch the two around
01:05and get four plus six equals ten. We can also figure out that if we start with ten as a
01:12group and subtract six, we will be left with four. When we start with ten and take away
01:22four, then you will be left with six. Now we can see more of the relationship between
01:31addition and subtraction. This is really similar to what you might have learned with a math
01:37mountain from one of my other videos. Ten can be made up of six and four. We can say
01:46that ten minus four equals six. We can also ask the question, what is ten subtract six?
01:55You might know the answer is four, but we can get that using addition to find the number
01:58that makes ten when added to six. For example, we can start at the six here and count up
02:04until we get to ten. Starting at six, we count seven, eight, nine, ten. We counted
02:14four numbers, so the answer is four. We figured out the subtraction problem by finding the
02:19number that adds up to ten when added to six. Great job! That was a lot of learning, but
02:26we are now ready for the problems to power my ship. Here we have a problem that says,
02:33to solve ten minus three equals blank, we can also write three plus blank equals ten.
02:43There are a few different ways to look at this problem. One way is to draw objects.
02:48We are going to use circles today. The first part of the problem says we start with ten
02:53and take away three, so let's start with ten circles. Take a minute to figure it out.
03:04One way we can start is by knowing we start with ten and cross out three circles and that
03:08leaves us with seven circles left. The first blank is now filled. The last part of the
03:15problem says we can also write three plus blank equals ten, so three plus what equals
03:21ten? The three circles plus the seven circles will equal ten. Amazing job, guys! Let's look
03:30at another question to fill my ship's power. The problem says to solve nine subtract three
03:38equals blank, we can also write three plus blank equals nine. To find the answers to
03:46the blank, we will use a math mountain this time. Why don't you try this on your own for
03:51a minute and then come back? We start with nine at the top, which is the total. Three
03:59is one of the addends on the bottom. Just for fun, I want to start by solving the last
04:04part of this problem. Three plus what equals nine? What number makes nine when added to
04:12three? To do this, we count up from three to nine and see how many numbers we count
04:18up. So we start at three and count four, five, six, seven, eight, nine. How many numbers
04:26did we count? The answer is six. Three plus six equals nine. Great job! Now for the first
04:35part of the problem, it asks what is nine subtract three? We know the answer is six
04:42because we know nine is made up of six and three. Amazing! My ship is now fully charged.
04:52Thank you so much for helping me. I am headed back to Earth now. See you guys later. Goodbye!