The purpose of this activity is to measure a length that is over 100 length units long and count the number of units using grouping methods. Some students may count by 1, others may organize their cubes into groups of 10. Although some students may attempt to represent their counts with a written number, the emphasis is representing the length of the string with a drawing. Students will identify written numbers in the next activity and practice writing them in the next lesson.

When students look for efficient ways to count the cubes, such as grouping them by tens, they look for and make use of base-ten structure (MP7).

• Invite previously identified students to share.
• “¿Cómo contaron los cubos?” // “How did you count the cubes?” (We organized them into groups of 10. When we couldn’t make any more groups of 10 we left the singles. Then we counted the groups by 10 and counted the singles last.)

The purpose of this activity is for students to match representations of tens and ones to written numbers up to 100. Students may count by tens and ones. Some students may see that 10 tens can be grouped to make 100. After they count, students match the written number to the picture. This matching task gives students opportunities to analyze base-ten diagrams and two- and three-digit numbers closely and make connections (MP2, MP7).

• Invite students to share how they matched their cards.
• Display all cards that show 100 or more.
• “¿Qué observan acerca de estas representaciones?” // “What do you notice about these representations?” (They all have 10 tens. There are more than 100 cubes.)