 There are other ways aside from traditional use methods that kids can use to solve problems. This video will cover the three different strategies that kids can use to solve addition and subtraction problems. Tara has 62 pencils. Samuel gave her some more pencils. Now she has 91 pencils. How many pencils did Samuel give her? Today we're going to solve this problem with the open number line. The open number line is a number line with no numbers or markers. It starts out empty and the students add the numbers to solve the problem. The student makes jumps along the number line and records both the value of the jump as well as the number landed on. The students use benchmark numbers, usually numbers that are multiples of 10, in order to break the problem down using friendlier numbers. I started at 62 and then added 20 to get to 82. Then added 8 to get to 90, and then added 90 to the benchmark, and then added 1 to get to 91. And Samuel gave her 29 pencils. Good. How did you know it was 29 pencils? They added 28 and 1 to get 29. Has anyone solved this in a different way? Great. You can also use subtraction to solve problems with open number lines. This student used the benchmark numbers 70 and 90 to make it easier to calculate the answer. I started at 91 and subtracted 1 to get to the benchmark 90, and subtracted 28 to get to 70, and subtracted 8 to get to 62. My sentence is Samuel gave Tara 29 pencils. How did you know it was 29 pencils? Because I added the 1, 20 and 8. Great. Okay, boys and girls, raise your hand if you can tell me how are these two solutions the same? Sienna? They both have the same answer, 29. Great. And how are these two solutions different? Key good. Well, the top one starts at 62 and ends at 91, while the one at the bottom starts at 91 and ends at 62. Good job. By hearing other students explain the strategy, students recognize that there is more than one way to solve a problem. I like the open number line because it gives me a clear idea of how the children are thinking, and when they are making a mistake, I can see it right away. Another strategy students can use is compensation. Students can add to or subtract from a number to make it a friendlier number, which is easier to work with, and then compensate at the end to keep the total correct. Tell me what you did to solve this problem. I started at 82, I added 40, minus one, and lined it at 121. They know when 39 is close to 40, so they just go ahead and add 40 and then take away one, and then they've got 39, which is actually a hard number to add, but with compensating, it's very easy. Compensation is a good strategy to use when a number you are using is close to a friendly 10. Here, 39 is close to 40. We can build on students' understanding of numbers to use different strategies, such as breaking up numbers. Breaking numbers apart using their place value is a strategy that makes adding easier. We're going to use breaking up numbers to solve this problem. What we're going to do is add 30 and 40. The teacher adds the 10s first. And that's going to give us 70. Then we're going to add 8 and 7. Then she adds the ones. To give us 15, then we add 70 plus 15 to give us 85. Ultimately, it does not matter which strategy a student uses. Can you tell me why you like this strategy? Because when you break up numbers, that means you can break up the 10s and 1s. That means, and if you do it piece by piece, that makes it easier. Good. Good answer. What is most important is that they understand how they got their answer and are able to explain it. Providing a variety of ways to solve a problem will allow more students to be successful and empower them to solve problems in ways that make sense to them.