Skip counting by 10s to 100 from random numbers

General

Students learn to skip count by 10s to 100 from random numbers. They practice skip counting forward and backward.

Standards

CCSS.Math.Content.2.NBT.A.2

Learning objective

Students will be able to skip count by 10s to 100 from random numbers.

Introduction

Have students form pairs. Give each pair a set of number cards with pairs containing numbers to 100. Have the students play memory with the cards finding the number pairs.

Instruction

Start by explaining what tens are. Tens are a group of ten and end with a 0 in the ones place. It is useful to know what tens are when you plan to skip count by tens. When you skip count by tens, the number in the tens place changes, and the number in the ones place stays the same. Show a number sequence in which jumps of 10 are made. Start at 8 and continue counting until 98. Point at the numbers as you say them and ask students to count along. Next show a number line in which the jumps of 10 are shown. Ask students to determine which numbers belong at the question marks. Then ask students to skip count forward and complete the number sequence. Have students write their answers on a sheet of paper or mini whiteboard and hold up their answers so you can check their work. Then tell students that you can also skip count backward by 10s. Point at the numbers as you say them and have students say the numbers along with you from 94 to 4. Show them a number line which shows the jumps of ten. Ask students to determine which numbers belong at the question marks. As a class practice skip counting backward by 10s. Have students determine which numbers are missing and write them on a sheet of paper or mini whiteboard. Have them hold up their answers to check their work. Erase the grey squares to show the correct answers. Ask students to practice skip counting forward and backward by 10s by completing the number sequence and saying which numbers are missing.

Check that students are able to skip count by 10s to 100 from random numbers by asking the following questions:
- What are tens?
- How do you skip count by 10s?
- Skip count forward by 10s and start at 39.
- Skip count backward by tens and start at 83.

Quiz

Students are initially asked to skip count with the visual support of a number line. Then they must skip count without the number line, then skip count backward, and they must also solve sequences with counting forward and backward.

Closing

Discuss with students that it is important to be able to skip count by 10s to 100 from random numbers so that you can easily count and make calculations easier. To check that students have understood, ask them to fill in the missing numbers from the number sequence. Then show a map on the interactive whiteboard. They must find the route that Lars takes when starting at 36 and skip counting forward by 10s. The students should end at 86. Ask students which numbers they must follow. You can choose to draw the route as students count.

Teaching tips

Students who have difficulty with this learning goal can be supported by making use of the number line. This helps visualize the numerical jumps they are taking. Remind students that when they skip count by tens, the number in the tens place changes, but the number in the ones place stays the same. First practice skip counting forward, then practice skip counting backward.
For the memory game- an optional alternative or challenge would be to have students find pairs of tens numbers (say 21 and 31), or neighbor numbers (like 21 and 22). Any pairing can be made, as long as the number card sets are prepared in advance.