Have you ever noticed something special about numbers like 10, 100, and 1000? These numbers are called multiples of powers of 10. It might sound tricky, but it’s actually pretty simple!
Let’s start with the basics. When we multiply 10 by 10, we get 100. If we multiply 100 by 10, we get 1000. These numbers are all powers of 10. But what if we want to multiply other numbers by 10, 100, or 1000? There’s a cool trick for that!
When you multiply or divide a decimal number by 10, 100, or 1000, you can use a simple trick: move the decimal point. Here’s how it works:
The number of places you move the decimal point depends on the number of zeros in the number you’re multiplying or dividing by. For example, if you’re multiplying by 10 (which has one zero), you move the decimal one place. If you’re multiplying by 100 (which has two zeros), you move it two places.
Let’s look at some examples to see how this works:
1.5 multiplied by 10 means we move the decimal point one place to the right (because 10 has one zero). So, 1.5 becomes 15.
1.5 multiplied by 100 means we move the decimal point two places to the right (because 100 has two zeros). So, 1.5 becomes 150.
1.5 multiplied by 1000 means we move the decimal point three places to the right (because 1000 has three zeros). So, 1.5 becomes 1500.
Let’s say Albert is paying people to deliver newspapers. He pays each person $10.40 for one hour of work. If Albert needs to pay 100 people, how much money does he need?
To find out, we multiply $10.40 by 100. Since 100 has two zeros, we move the decimal point two places to the right. So, $10.40 becomes $1,040. Albert needs $1,040 to pay everyone for one hour of work.
Whenever you multiply a decimal by 10, 100, or 1000, just move the decimal point to the right. Count the zeros to know how many places to move it. This trick makes multiplying by powers of 10 super easy!
Decimal Point Dance: Create a fun game where you use a number line drawn on the ground or a long piece of paper. Write numbers like 1.5, 2.3, and 4.7 on cards. Have the children stand on a number and “dance” the decimal point to the right by moving the number of steps equal to the zeros in 10, 100, or 1000. For example, if they are multiplying by 100, they move two steps to the right. This helps them visualize how the decimal point moves.
Power of 10 Hunt: Go on a scavenger hunt around the classroom or at home to find items that come in packs of 10, 100, or 1000. Examples could be a box of 10 crayons, a pack of 100 sheets of paper, or a bag of 1000 beads. Discuss how multiplying the price of one item by 10, 100, or 1000 would help find the total cost of the pack.
Real-Life Application: Ask the children to think of a situation where they might need to multiply by 10, 100, or 1000 in real life. For example, if they have $5 and want to know how much they would have if they saved 10 times that amount, they would multiply $5 by 10. Encourage them to share their examples and explain how they would move the decimal point to find the answer.
Sure! Here’s a sanitized version of the transcript:
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[Music] These numbers have something in common. Can you spot what it is? We call these numbers multiples of powers of 10. That’s a bit of a mouthful, isn’t it? But don’t worry, it’s not as complicated as it sounds. Ten, one hundred, and one thousand are all examples of multiples of powers of ten.
We can multiply the number ten by ten, which we know is one hundred. We can then multiply one hundred by ten, which is one thousand. Did you know that we can also multiply this number by ten? There are simple tricks we can use when multiplying and dividing a decimal number by these multiples of powers of 10. These tricks will be especially helpful when dealing with large quantities of money.
When we multiply or divide a decimal number by multiples of powers of 10, all we have to do is move the decimal point to the right or to the left. The first trick to remember is which direction we move our decimal point. When we are multiplying, we need to move the decimal place to the right. When we are dividing, we move the decimal place to the left.
[Music] The second trick to remember is that no matter whether we are multiplying or dividing decimals by 10, 100, or 1000, we move the decimal point the same number of places as the amount of zeros in the number.
Let’s have a closer look to show you just how all of this works. When multiplying a decimal by 10, 100, or 1000, we move the decimal point to the right. We can see that by doing this, the number becomes bigger.
Let’s take the number 1.5. What is 1.5 multiplied by 10? Because we are multiplying 1.5 by 10, and 10 has one zero, we move the decimal point one place to the right. When we move the decimal point one place to the right, we get the answer 15. Therefore, 1.5 times 10 equals 15.
What happens if we want to find out what 1.5 times 100 is? Well, we know that 100 has two zeros, so to solve 1.5 times 100, all we need to do is move the decimal point two places to the right. This means 1.5 times 100 equals 150.
How do you think we might find out what 1.5 times 1000 is? That’s right! Because there are three zeros in one thousand, we move the decimal point three places to the right. Now we know that 1.5 times one thousand equals 1500.
Let’s look at another example. Albert is paying people to deliver newspapers door to door. He pays each person $10.40 for one hour of work. If Albert is paying 100 people to do the newspaper route, how much money will he need to have to make sure everyone gets paid?
Let’s break this question down. We know that every person who is delivering papers gets paid $10.40. Albert needs to pay 100 people this amount, which means we need to multiply 10.40 by 100. We know that we have to move the decimal point one place for each zero in the number we are multiplying by. Because we are multiplying by 100, we need to move the decimal point two places to the right.
Albert will need to have $1,040 to pay everyone for one hour’s work. Remember, if you are multiplying a decimal by ten, one hundred, or one thousand, you move the decimal point to the right. And don’t forget to count the zeros in these numbers because they will tell you straight away how many places to shift your decimal.
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This version maintains the educational content while removing any unnecessary or informal language.
