## Explain how to solve for an unknown addend

## Missing addend | maths concept for kids | grade 1

I’ll start by going through our addition facts. My students will stand up and form a wide circle in the class. I have a beach ball on hand for various games, and they will play “Beach Ball Math Stats” with us today. I’ll give the ball to my starting player and instruct them to toss it around the circle to another student, who will then have to address an additional fact that I’ll say. If the student is confused, any volunteers can lift their hand as a lifeline and assist them by stating the correct answer. If the student who catches the ball correctly answers the question, he or she will sit after passing the ball to another student. Only those who have not yet had a turn will stay standing until a student has sat. The game will go on until the last person has had a chance to answer a question. Interaction in the Whole Community Time limit: 5 minutes Our number system has a pattern and structure, and we want to start pointing those elements out to our students as early as possible so that they can establish a solid foundation in decomposing numbers (MP7). I’d like them to reflect on the structure and relations between the two linked addition and subtraction problems because this will help us practice fact families in a few days. Since not all students see the link between addition and subtraction on their own, I’ll use this lesson to point it out and help them see it.

## Missing addends: finding a missing part for kids

I began by discussing the issue of my students’ easy access to action pieces (their fingers). Then I expanded on that and moved on to problems that they could solve abstractly with imagery if they needed to use manipulatives. (MP2.) This will have them thinking critically and making connections before we start our lesson. Interaction in the Whole Community Time limit: 10 minutes To introduce the idea of an unknown addend, I’ll use a story issue. The following problem and discussion points will be used by me.

Sara is the subject of our inquiry; we don’t know what she gave him, so we’ll call it x. I’ll write the equation x+6=10; we’re looking for a number that, when multiplied by 6, equals 10. We’ll replace the x with the correct number once we’ve found the answer. Then we’ll see if what we learned supports the number sentence.

I’ll bind 10 unifix cubes and split off 6 to see what’s left; the answer is 4. I’ll clarify to my students that we’ll be subtracting to find out what’s being introduced. Since I am aware that this idea is very abstract, I am using this concrete approach with cubes to introduce it to my students. There are a variety of methods for solving an unknown addition equation, but I’m going to start with the concrete approach in order to clarify, teach, and hopefully reach all of my students. OA.D.8 (1.OA.D.8) Several of my students have the higher-order reasoning skills to solve for uncertain whole numbers in an equation using counting up and/or math truth fluency. However, by incorporating this idea with a specific relation, all of my students would be able to see the correlation between using an x for the unknown. The abstract thinking process of searching for the unknown is something that First Graders are working towards (MP2). They must learn to choose methods that will aid them in reasoning quantitatively. Please see the image in the resource section for an outstanding example of one student counting up and another student solving with her cube tower. I’ll work on two more issues with my class, both of which are close to the one above.

### Unknown addend

To find the missing addend, students can use number bonds and counters as a tactic. The relationship between addition and subtraction will be understood by the students. Counting can also be used because it is similar to addition and subtraction. This is a showcase lesson plan for the College- and Career-Ready Standards.

To add 2 + 6 + 4, multiply the second two numbers by ten, resulting in 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition) MA2015 (2016) Grade: 1 Math MA2015 (2016) Grade: 1 Math MA2015 (2016) Grade: 1 Math 4 ) Consider subtraction as a problem with an undefined addend. [OA4-1]

Subtract 10 from 8 by finding the number that, when added to 8, equals 10. MA2015 (2016) Grade: 1 Math MA2015 (2016) Grade: 1 Math MA2015 (2016) Grade: 1 Math 5 ) Make the relation between counting and addition and subtraction (e.g., by counting on 2 to add 2). [OA5-1] Alabama is a state in the United States Alternative Achievement Requirements

Students can use a variety of techniques to solve missing addend problems, including number bonds, counting on, and relating addition and subtraction information. Counting will be linked to addition and subtraction for the students. The students can solve problems involving missing addends in the real world.

### 2nd grade math: addition/subtraction – how to solve for a

(This is one of the occasions of math where the language we use is so narrowly based on small bits of material – “silos” – that we end up shooting ourselves in the foot when it comes to teaching the underlying concepts.)

Students must realize that any number is made up of other numbers in order to grasp this concept. Finding one of the numbers that make up another number, the minuend aka, the sum, is all that subtraction entails.

There is only one thing in the category when you point to the first object and say “1.” When you say “2” and point to the second thing, you’re not referring to that item; rather, you’re referring to the size of the category that includes that item and the first one you counted. When you count “3,” you’re not marking that item; rather, you’re representing the size of the category that includes that item and the two you previously counted. And so forth.

To put it another way, each count does not mark the object you are counting. It indicates the size of the group, which includes all of the things you’ve counted so far. We call this concept “cardinality.”