100 chart, one per student; bag of 50 small manipulatives (e.g., connecting cubes) of the same color, 1 bag per student

Students need to be able to recognize and identify all numerals to 100 before using a 100 chart.

Activity 1: Counting by 10s on the 100 Chart
If students are not familiar with a 100 chart, allow several minutes of time for them to tell things they notice about it. When students skip count on a 100 chart, visual patterns will emerge that help them see skip counting in a more concrete representation.

To begin, ask students to point to the numeral 10 and place a cube on 10. Ask them to count 10 more spaces and tell what numeral is at the space where they stopped counting (20). A cube is placed on 20 and then students count 10 more spaces, etc. When all multiples of 10 have been covered with a cube, ask students to tell something they notice about these numerals. Students might say:

• They all have a zero.
• It goes 1, 2, 3, 4, 5, 6, 7, 8, 9 in the tens place.
• We skip 10 spaces when we counted by 10s.
• The 10s' boxes are all on the right side of the 100 chart.
• It's counting by 10s!

On Recording Sheet 1, 100 Chart for Counting by 10s, ask students to color in the boxes that show counting by 10s.

Activity 2: Counting by 2s on the 100 Chart
Complete the same activity for students to notice patterns when counting by twos. Ask students to count two spaces and place a counter on that numeral. Students continue counting two places and placing counters on the numerals until they reach 100. Then ask them to tell what they notice on the 100 chart when they are counting by twos. On Recording Sheet 2, 100 Chart for Counting by 2s, ask students to color all of the boxes covered by a cube.

After both charts have been completed, students will have two 100 charts colored, one counting by 10s and the other counting by 2s. Ask students if they notice any patterns on the charts that may help them remember how to count by twos and tens. For example, when counting by 2s, the chart is colored in straight vertical columns, every other column. When counting by 10s, the last column is colored straight down and every number has a zero in it. Practice counting by 10s and 2s as a group while pointing to a large 100 chart. When students count in unison, they can count further in the counting sequence than if they were counting by themselves.

Activity 3: Counting by 10s and 2s from Any Number on a 100 Chart
Students count by 10s and 2s beginning with other numbers. Tell students they may use the hundreds chart to help them. Several examples of questions to ask:

• Begin at 48 and count on by 10s.
• Begin at 77 and count on by 2s.

Recording Sheets:

• Recording Sheet 1, 100 Chart for Counting by 10s http://mdk12.org/instruction/lessons/images/Gr1_1A1aLS_a.pdf
• Recording Sheet 2, 100 Chart for Counting by 2s http://mdk12.org/instruction/lessons/images/Gr1_1A1aLS_b.pdf