The purpose of this activity is for students to consider the possible consequences of estimating a quantity instead of finding an exact amount. Students consider different situations and distinguish between those where estimating might have a negative effect on the situation, and those where estimating won’t have much effect on the situation at all. When students think about the real-world implications of estimating in a situation, they model with mathematics (MP4).

• “How did you decide whether you would estimate or find an exact amount?” (I thought about whether or not it would mean that there wasn’t enough of something or too much of something. If that could happen, then I would find an exact amount.)

The purpose of this activity is for students to estimate the number of objects in a group and consider situations where counting to find an exact amount might be necessary. Students should be encouraged to estimate quantities rather than try to count them. Some students may not have a reasonable estimate, but can be successful in this activity if they sort the photograph based on whatever estimate they consider is “about right.” This sorting task gives students opportunities to analyze different quantities closely and make connections (MP2, MP7).

• Invite students to share how they sorted their cards.
• Display the questions about Andre.
• Invite previously identified students to share their explanations.