Lesson 2: Adding Two- and Three- Digit Numbers Show /en/additionsubtraction/introduction-to-addition/content/ Adding larger numbersAs we saw in Introduction to Addition, you can often use counting and visuals to solve basic addition problems. For instance, imagine that 3 people are going on a trip and 2 more decided to join. To find out how many people were going total, you could represent the situation like this: Once you look at the problem visually, you can count and see that 5 people are going on the trip. What if you have a bigger problem to solve? Imagine that a few groups of people are going somewhere together. 30 people travel on one bus, and 21 travel on another. We could write this as 30 + 21. It might not be a good idea to solve this problem by counting. First of all, no matter how you choose to count, it would probably take a pretty long time to set up the problem. Imagine drawing 30 and 21 pencil marks on the page, or counting out that many little objects! Second, actually counting the objects could take long enough that you might even lose track. For this reason, when people solve a large addition problem, they set up the problem in a way that makes it easier to solve one step at a time. Let's look at the problem we discussed above, 30 + 21.
We can see that 30 + 21 and mean the same thing. They're just written differently.Solving Stacked Addition ProblemsTo solve stacked addition problems, all you need are the skills you learned in Introduction to Addition.
Try This!Solve the addition problems below. Then, check your answer by typing it into the box. Adding Very Large NumbersStacked addition can also be used for adding larger numbers. No matter how many digits are in the numbers you're adding, you add them the same way: from right to left.
Try This!Add these large numbers. Then, check your answer by typing it in the box. Using CarryingOn the last page, you practiced adding vertically stacked numbers. Some problems need an extra step. For example, let's look at the following problem: Our first step is to add the digits on the right— 5 and 9. However, you might notice there isn't room to write the sum, 14. When the sum of two digits in a math problem is greater than 9, the normal way of adding stacked numbers won't work. You'll have to use a technique called carrying.
As you carry, be careful to keep track of the various numbers. If you're writing problems down, be sure to write the carried digits in small print above the column of digits to the left. Try This!Solve these problems by carrying. Then, check your answer by typing it in the box. Practice!Practice adding these problems. You'll have to use carrying to solve some of the problems. There are 4 sets of problems with 3 problems each. Set 1Set 2Set 3Set 4/en/additionsubtraction/video-addition/content/ How many 5 digit palindromes are there?∴ total ways =9×10×10=900.
How many 3 digit numbers have the property that their digits taken from left to right form an AP or GP?If we count the GPs we get: 124, 139, 248, 421, 931, 842 a total of 6 GPs. Hence, we have a total of 42 three digit numbers where the digits are either APs or GPs.
What are some 3 digit numbers?3-digit numbers are those numbers that consist of only 3 digits. They start from 100 and go on till 999. For example, 673, 104, 985 are 3-digit numbers.
What is a 3 digit palindrome number?The three digit palindromes are 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, 212, 222, . . . One could list all of the three digit palindromes to see how many there are, but a more general formula can be derived to find the number of k-digit palindromes, where k is any whole number greater than one.
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