What we are currently learning in Math
Addition and Subtraction Strategies
This next unit in math will focus on adding and subtracting first within 100 and then within 1000. Students will be learning strategies on how to add and subtract both with and without regrouping. Much of what you will see your child do is new to you. It's not how we learned math when we were in school. However, there is a reason behind why we are doing it this way. We are showing students the concrete reasons on how when you borrow or carry over, that we are either transferring either a ten into ten ones or ten ones into a ten and later on showing how we can break a hundred into 10 tens and 10 tens can be combined to form a 100. We will be teaching the standard algorithm that we learned growing up, so that they are exposed to it, but it is not one of our second grade standards. Interestingly enough, it is not considered a standard until 4th grade. Students can use the standard algorithm to check their answer but we are going to ask them to show their work in another way.
Over the next couple weeks we will be learning several different stategies for adding and subtracting such as using place value blocks, drawing hundreds, tens and ones, breaking apart numbers into hundreds, tens and ones and using number lines. Once we have learned and practiced all strategies, students will be able to choose the strategy that works best for them. Please remember that while we briefly teach the standard algorithm, students will only be able to check their answer this way.
Included below are some of the anchor charts that we are using at school. They do not show regrouping but I am working on creating videos for each strategy and I'll be posting them soon on our class stories on Class Dojo.
Over the next couple weeks we will be learning several different stategies for adding and subtracting such as using place value blocks, drawing hundreds, tens and ones, breaking apart numbers into hundreds, tens and ones and using number lines. Once we have learned and practiced all strategies, students will be able to choose the strategy that works best for them. Please remember that while we briefly teach the standard algorithm, students will only be able to check their answer this way.
Included below are some of the anchor charts that we are using at school. They do not show regrouping but I am working on creating videos for each strategy and I'll be posting them soon on our class stories on Class Dojo.
Addition Strategies
Subtraction Strategies
Mental Math - 10 more, 10 less, 100 more, 100 less
Our next mini unit in math is all about mental math. By the end of this mini unit we want students to be able to mentally add and subtract 10 or 100 from any number within 1,000. We start this by reminding them of place value. We talk about how when we add or subtract 10's or 100's, then it's the number in the ten's place or hundred's place that is changing. For example if we were adding/subtracting 10 to the number 57, if we added ten we would get 67 (ten's place went up one) and if we subtracted 10, then the number would be 47 (tens place went down one). The same thing happens when we add or subtract a 100. If we started with the number 865, if we added a 100, we would get 965 (hundreds place went up one), if we subtracted 100 then we would have 765 (hundreds place would go down one).
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Word Problems
Our next unit in math is word problems. Yes, I can hear the groans from here. It's okay though, we've got a plan. Word problems aren't quite as bad as they sound and we have several strategies in place for how we are going to solve them. First, we introduced students to MOAT, which is our school acronym for how we are going to solve word problems. In addition to MOAT, I also taught students that there are 3 parts to a word problem. The start, the change and the result. The start is what we start with at the beginning of the problem. Sometimes we're given this number and sometimes we have to find it out. The change is the action in the word problem, this is the change that happens to our first number, it could be adding or subtracting. To help us identify the change that happens, I ask students to look for the verb, or action word in the problem. It could be someone giving you something or giving it away, baking, eating, picking, finding etc. Sometimes the change is given to us and sometimes we have to find it because it's unknown. Then the last part is the result, what we end up with after the action. The result is what we get after we either add or subtract. Like the other two parts, sometimes we are given the result and sometimes we have to find it.
It's important to have students mark up and label the word problem, because then they can plug it into a formula to help them solve it. This basic formula is S + C = R or S - C = R. Sometimes there are multiple C's in the equation. But knowing and using these equations will help your child become a word problem master. |
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Addition and Subtraction Strategies to 20
Our next unit in math is all about math fact fluency. It is a standard in second grade that students are able to add and subtract fluently to 20. Now you might be asking, what do you mean by fluently. This means that students don't have to think about the fact, they just automatically know it.
There are several different strategies we teach when we are talking about math fact fluency. These strategies include doubles, doubles plus one, counting on, counting back, making a ten, using a number line, skip counting and fact families. Doubles is just what it sounds like. It's using doubles facts to help us learn our math facts. There are all sorts of fun songs out there to help us learn our doubles facts. Doubles plus one, is when you think of a doubles fact and just add one to it. Counting on means you are looking at an addition sentence such as 9 + 4, and put 9 in your brain and count on 4 from there. Counting back is the same strategy, only you are working with subtraction sentences and thinking of the bigger number (first number in a subtraction sentence) and counting backwards. Making a ten involves students breaking apart the smaller number, to help make a ten with the first number and then adding on. Here's an example, let's say we were doing 9 + 4 again. We could break the number 4 into 3 +1, then add the 1 to the 9 to make a 10, then we can easily add 3 more. This sounds complex, but it's something many adults do frequently without really noticing they are doing it. We also have skip counting, this is a skill we learned in the previous unit but we are also working on it in this unit by counting by 2's, 5's or 10's. Last, but not least, we have fact families. Fact families are 3 related numbers. For example 2, 3, 5 are a fact family. When you have a fact family you can write 4 different math sentences, 2 addition and 2 subtraction. Using our fact family example of 2, 3 and 5, the number sentences we can write are as follows:
2 + 3 = 5
3 + 2 = 5
5 - 2 = 3
5 - 3 = 2
Knowing how fact families work can help students figure out missing addend questions such as 6 + ___ = 11, if they don't already know it, they can use what they know about fact families to re-write the sentence as 11 - 6 = ? to solve for the answer.
If your child is unable to quickly respond when you ask them a math fact within 20, I highly suggest having them practice at home. As we will be working on may different addition and subtraction problems all year long and knowing their math facts will make math easier for them. They can practice using several of the games that we have been assigning for homework, or by using flashcards.
Below are some video's we've been using in class to learn the different strategies.
There are several different strategies we teach when we are talking about math fact fluency. These strategies include doubles, doubles plus one, counting on, counting back, making a ten, using a number line, skip counting and fact families. Doubles is just what it sounds like. It's using doubles facts to help us learn our math facts. There are all sorts of fun songs out there to help us learn our doubles facts. Doubles plus one, is when you think of a doubles fact and just add one to it. Counting on means you are looking at an addition sentence such as 9 + 4, and put 9 in your brain and count on 4 from there. Counting back is the same strategy, only you are working with subtraction sentences and thinking of the bigger number (first number in a subtraction sentence) and counting backwards. Making a ten involves students breaking apart the smaller number, to help make a ten with the first number and then adding on. Here's an example, let's say we were doing 9 + 4 again. We could break the number 4 into 3 +1, then add the 1 to the 9 to make a 10, then we can easily add 3 more. This sounds complex, but it's something many adults do frequently without really noticing they are doing it. We also have skip counting, this is a skill we learned in the previous unit but we are also working on it in this unit by counting by 2's, 5's or 10's. Last, but not least, we have fact families. Fact families are 3 related numbers. For example 2, 3, 5 are a fact family. When you have a fact family you can write 4 different math sentences, 2 addition and 2 subtraction. Using our fact family example of 2, 3 and 5, the number sentences we can write are as follows:
2 + 3 = 5
3 + 2 = 5
5 - 2 = 3
5 - 3 = 2
Knowing how fact families work can help students figure out missing addend questions such as 6 + ___ = 11, if they don't already know it, they can use what they know about fact families to re-write the sentence as 11 - 6 = ? to solve for the answer.
If your child is unable to quickly respond when you ask them a math fact within 20, I highly suggest having them practice at home. As we will be working on may different addition and subtraction problems all year long and knowing their math facts will make math easier for them. They can practice using several of the games that we have been assigning for homework, or by using flashcards.
Below are some video's we've been using in class to learn the different strategies.
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Understanding Place Value
Our first unit in math is all about understanding place value. We work on this unit first because it sets a solid foundations for which we build upon for the rest of the year. During this unit we first focused on learning vocabulary such as ones, tens, hundreds and how we use those terms with numbers. For example in the number 459, there is a 4 in the hundreds place which stands for 400, there is a 5 in the tens place, which stands for 50 and there is a 9 in the ones place which stands for 9 ones. Once students have mastered this we started to talk about bundling. When we have more than 10 ones, we can bundle 10 ones and make a ten and when we have more than 10 tens, we can bundle them to make a hundred. We practiced this skill using place value blocks in the classroom and practiced exchanging 10 ones for a tens rod, and exchanging 10 tens for a hundreds flat block.
From here we started to discuss the different ways that we could write numbers. We have standard form, which is just the number written out in number form (i.e. 345, 952 or 847). We also discussed how to write the number in word form (i.e. 259 would be written as two hundred fifty nine and 719 would be written as seven hundred nineteen. We also started to learn about expanded form which is taking a number like 462 and breaking it down into it's hundreds, tens and ones and adding addition signs. So 462 in expanded form would be written as 400+60+2.
From here we moved onto comparing two and three digit numbers. They have previously practiced in first grade how to compare two digit numbers and in second grade, we add on to now comparing three digit numbers. We talked how when comparing two numbers we always start with the biggest place, so if given the number 564 and 932 to compare, we would first look at the hundreds place, one number has a 5 and the other number has a 9. We would draw the < sign, because we want to "eat" the bigger number. We also practiced using terminology such as greater than, less than and equal to.
From here we started to practice skip counting by 5's, 10's and 100's. We discussed the patterns we noticed when skip counting and how that effected place value. We also started examining a 120 chart closely to notice the patterns within it. For example, when looking at a 120 chart, when you look down a column, the ones place stays the same and it is the tens place that is increasing. When you look across a row, we notice that the tens place mostly stays the same and it is the ones place that is increasing by one as you move across the row.
See below for pictures of what we are learning, as well as some of the videos we have been watching in class to help us understand place value.
Place Value Videos We Have Used In Class
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