Early math review
Subtracting 2-digit numbers without regrouping 1
Sal subtracts 23 from 65 by thinking about tens and ones.
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- Show me how to find the product of 6X5 using breaking apart
- Why does Algebra exist even though we don't use it in life?(3 votes)
- if you don't use it doesn't mean other they don't. for example accounting uses algebra to get exact amount of money. bakeries use it for cake and other dessert making. it is useful and many people would appreciate it in their field.(15 votes)
- what is a column(8 votes)
- a column is just a vertical area, so all the elements in the column are stacked on top of each other.
you can see in the video that the ones "column" is just the vertical area that he dotted around and all the elements inside that column (the 5 ones, the 3 ones and the 2 ones) are put each one on top of the other.(5 votes)
- 65-23 is the answer to life, the universe, and everything. (or at least it is in A Hitchhikers Guide To The Galaxy ;) )(6 votes)
- Reason being that in ACSII, 42 denotes the asterisk *. 42 therefore points to anything and everything else out there.(7 votes)
- Do you borrow with negative numbers(6 votes)
- Hi Lynel,
No it is not even possible to borrow with negative numbers.
Hope this helps
- Sarah(6 votes)
- I am in 2nd grade do I need to know this(5 votes)
- Yes, you will use all of this math in your daily life in the future, for buying things, for finding how many things you have, etc. You will also use all of this math in school.(5 votes)
- Khan Academy should group kids up! so they can work to gether.(6 votes)
- whats the difrent betwen 1453 and 246363(3 votes)
- The difference between 246363 and 1453 is 244910.(6 votes)
- When you "carry" digits what is that referring to(4 votes)
- Hi Lynel. A carry is a digit that is transferred from one column of digits to another column of more significant digits. For ex. when 6 and 7 are added to make 13, the "3" is written to the same column and the "1" is carried to the left.(4 votes)
- How do you subtract 47-51?(3 votes)
- You would end up with a negative number.(3 votes)
- [Voiceover] Let's try now to subtract some two-digit numbers. Over here, we have 65 minus 23, and I encourage you to pause the video and see if you could figure this out. I'm assuming you've had a try at it. Let's do it together. The way I like to do it is I start in the ones place, and the numbers in the ones place I've colored them in in yellow, so this right over here is the ones place. This over here in purple is the tens place. I could even do a column here, where everything in yellow, this is the ones column. I guess you could think of it that way, everything there is in the ones place. They're representing a certain number of ones, and then everything in the second column, everything in the second column is in the tens place. They represent a certain number, a certain number of tens. 65 is six 10s and five ones. 23 is two 10s and three ones. One way to do it is, say, let's look at the ones place first. I'm taking three ones away from five ones. Five ones minus three ones is two ones. Then, you can go to the tens place. Six 10s minus two 10s, well, that's going to be four 10s, four 10s, and there you have it. This is equal to 42, and once again, I could have written it multiple ways. I could have written it like this. I could have written 65 as 6 tens, six tens, + 5 ones, plus 5 ones. I didn't write over here because when I have something in this place, that means it's tens, but here I can write it out, 6 tens. If I'm subtracting 23, that's the same thing as subtracting two 10s, subtracting 2 tens, and then subtracting three ones, and then subtracting 3 ones, subtracting 3 ones. What's that going to be? Well, 5 ones - 3 ones is exactly what we have over here. It's going to be 2 ones, and 6 tens - 2 tens, well, that's just going to be 4 tens, 4 tens. 6 tens + 5 ones - 2 tens - 3 ones is going to be 4 tens and 2 ones, four 10s and two ones, or 42. 42 is equal to 4 tens + 2 ones. Hopefully, that makes a little bit of sense.