In the previous chapter, your student learned that two parts make a whole. In this chapter, your student uses an addition equation, called addition sentence, including a plus sign and an equal sign, to show two parts and a whole. 

Your student learns two different ways to apply addition. One way involves groups of people or animals actively joining. For example, 2 students may join 3 students to play a game so there are 5 students playing in all. Another way involves non-moving objects, such as counters, to focus on parts and a whole. 

Your student discovers patterns: When adding 0 to a number, the answer is the number. When adding 1 to a number, the answer is the next counting number. Finally, your student finds a missing partner number (addend) by adding or counting on to the given partner number. For example, for 5 + ? = 9, your student might use counters to figure out that 5 and 4 more equals 9. The goal of the chapter is to build an understanding of addition, not to memorize facts, so don’t worry if your student needs to count objects to find answers. Here are some activities you can use to practice with your student. 

• If you have two number cubes, change the sixes to zeros by covering the sixes with masking tape. Invite your student to toss the two cubes to make partner numbers. Encourage your student to name the partner numbers and the total, or the number in all. Expand the activity to include writing an addition sentence to show the parts and the whole. 
• Play “Get to Ten” using fingers to find missing partner numbers. One player holds up any number of fingers. The other player names the number of fingers and how many more fingers are needed to get to ten. For example, if a player holds up 7 fingers, the other player might say, “Seven fingers; it takes three more to get to ten.” 
• Make two sets of cards, numbered 1 through 5. Mix up the cards and spread them facedown on a table. Players take turns flipping over two cards to find partner numbers that make 6, for example, 2 and 4. If a player finds partners, the player gets to keep the cards. If not, the player turns the cards facedown. The player with the most cards wins!