Math- Week of 9/8
This week we will continue to learn strategies for adding within 100.
Our learning goals this week are:
- Using place value to add two numbers.
When using place value to add, we break both numbers into their expanded form and then add them together.
24 ----> 20 + 4
+35 ----> 30 + 5
50 + 9 = 59
Here is a video that explains this strategy.
We will also be using manipulatives to work on this, made of pipe cleaners and pony beads. Each bead represents adding a number in the ones place. (4 beads = 4). Students can make a "bracelet" out of 10 beads and a pipe cleaner to transfer the ones beads to the 10s place. (4 bracelets = 40 beads.) This helps the students understand how 10 ones can come together to make 10! It also prepares them for the advanced addition concept of regrouping or "borrowing." It is easy to make these as a tool to help students understand- you just need some pipe cleaners to string beads on and lots of pony beads to act as ones.
- Break apart a number to add.
When students use “Break Apart to add Tens and Ones,” they will break apart only one addend into its tens and ones. Then they will add the tens to the first addend, then add the ones. This video explains the strategy.
24 ----> 20 + 4
+ 35 ----> 30 + 5
4+5=9
20+30=50
50+9=59
So, 24 + 35= 59
- Using compensation to add.
When students used “Compensation,” they took ones from one of the addends to make the other addend a ten.
37 + 16 = ?
+3 -3
40 + 13 = 53
Here is a video that explains this strategy using blocks. Here is a video that explains this strategy as we write it.
- Choose a strategy to add two numbers. Students will choose a strategy to use while solving an addition equation, solve the equation, and explain the strategy they used.
- Solve two-step addition word problems. Many students find two-step word problems challenging because only one question is clearly stated, even though two steps are needed to solve the problem. To help with this, we break the problem into two simpler parts. Students use addition strategies they’ve already learned to solve each step one at a time.
Example:
You read 12 pages in the morning and 15 more pages in the afternoon. The next day, you read 20 pages. How many pages did you read altogether?
Step 1: First Day: 12 + 15 = 27
Step 2: Both Days: 27 + 20 = 47
Here is a video that explains this strategy.
Remember, the goal of this unit is to give students a variety of strategies with which they are comfortable. This will allow them to choose an efficient strategy depending on the situation or the numbers being added.
Math at Home
There are many real-life situations you can use to practice using addition strategies. You can add ages, amounts of money, numbers of objects, and so on. The maximum sum of objects for any activity in this chapter is 101. Here are a few activities you can use with your student:
- Say various 2-digit numbers. Have your student tell you how many tens and ones are in the number. For example, say, “How many tens and ones are in 43?” Your student should be able to tell you that there are 4 tens and 3 ones in 43.
- Ask your student to help you add an amount of money when shopping at a store (just dollars, not cents). Say, “This item costs $24 and this one costs $35. How much do they cost in all?” Give your student a notebook or a receipt to write the numbers and add them.
- Help your student practice using an open number line. For example, draw a number line without any numbers labeled. Have your student use the number line to add numbers you provide, such as 22 + 51. Ask, “How can you use the number line to add these numbers?”
Please help your child memorize their single-digit addition facts (for example, 6+6, 8+9, etc.). This is a critical skill for mastery by the end of 2nd grade. If you would like your child to practice at home, XtraMath is an easy way to do so—see the flyer in your child’s Friday Folder for details.