$khan academy multiplying decimals using area models$

#Khan academy multiplying decimals using area models plus#

And so we added it allįinding the combined area- the area of this plus theĪrea of that the area. The 6, we carried this 1 into the hundreds place. Multiplied the 2 times the 16, we just calculated Just doing that we justĬalculated that right over there. But notice we're really thinkingĪbout 20 times 60 is 120. So we're used to carrying theĢ down here and carrying the 1. So if you multiply 2 timesĪnd carry the 1. Said, oh, you know, I just throw a 0 down there. Into the tens place you've probably always This interactive exercise focuses on multiplying fractions and reducing them when possible. So 7 times the 10 or theħ0, plus 7 times 6, the 42. Use area models to show a visual representation of the product of two fractions. So 112, what you justįigured out right over here, is this area Right over here. Sum of both of these things, because you're multiplying 7 The 7 times the 1, you really multiplyingĬarry it when you add this carried 4, and But right when youĭid that 7 times 6, we essentially calculated The 4 in the tens place because it's a 40. With the 7 in the ones place and you do 7 times 6 is 42. Hey, Sal, why did we go through all of this business? I've seen before Did I add that up right? Let's see, this will be 11. Tens is 9 tens, plus 4 tens, is 13 tens, which is the same Let's see, in the ones place, you get a 2. Going to be 200 plus 120 plus 70 plus 42. So what's the area of thisĮntire thing going to be? Well, it's going to be theĢ00 plus the 120 plus- let me do it this way- it's So it's going to be 7 timesĦ or 42 square units of area. And then finally, what's theĪrea of this little section right over here? It's 7 high and it's 6 wide. This purple, and I'll thrown some blue in there, too. Section right over here? Well, it's 7 high Now what's 20 times 6? Well 2 times 6 is 12, In there from the 20 to make it clear that this Not the color I wanted to use- let me use

In your head 20 times 10 is just going to be. You could think of as 2 timesġ, and you have two 0's there. So we could figure out theĪreas of each of these sections, and then the area ofīe this product, is going to be the area of all Up by parts, because it'll be easier to compute, and weĬan see what part of the area those differentĬan think about what 10- so let me separate Is going to be 16 times 27, the area of thisĮntire rectangle. Right over here- and then the height of my rectangle, The product 16 times 27, what gives you the area ofĪ 16 by 27 rectangle. Point right over here, this line right over The 2 in the 10s place is representing 20. Which I want to do in that green color, the sixth, I've gone 10 slashes, or I'm representing 10 What's going on in the multiplication process. Was already in the order that we needed it to be, but it's good that we checked on that.Multiply 16 times 27.

And so we would expect this expression to be close to 4000, and indeed, that's what this choice is. So five times 800, that would be around, that would be 4000. 5.2, well let's just say that's roughly 5.

And so I'm already feeling good that this last choice sits down here. And so this should be about half of 800, so it should be around 400. Roughly equal to 1/2, and so, and 762, weĬould say hey, you know, that's, if we wanna be really rough, really, really approximate it, we could say, hey, it's roughly 800. Roughly equal to 50/100, roughly equal to 5/10, Now the second expression, 0.52 times 762. And so which of these is close to 38? Well this first one is 39.624, so that's actually the closest to 38. And so this first expression, this first product shouldīe roughly half of 76. It is 0.52, that's close to 50/100, that's close to a half, and so 76.2, that's close to 76. Multiplication using Box Method 2-Digit by 2-Digit This level 2 worksheet helps the 3rd grade, 4th grade, and 5th grade students gear up multiplying 2-digit by 2-digit numbers. So this first expression, 0.52 times 76.2, the way I think about With this level 1 area model multiplication worksheet, children will focus on 2-digit by 1-digit and 3-digit by 1-digit multiplication. And then we can estimate what these expressions should be equal to, what the products should be equal to, to think about the decimal. These have the digits three, nine, six, two, four, in that order. The digits three, nine, six, two, four, in that order. Is, we can say, hey look, the answer is going to have Might have realized is all of these expressionsĭeal with the same digits as 52 times 762. And these products, this is an exercise on Khan Academy, you can move them around so the product can be matched Told to match each expression to its product. That 52 times 762 is equal to 39,624, and then we're

Khan academy multiplying decimals using area models