Maryland Math 2.NOS.A.2

2.NOS.A.2 is a cluster heading. These are the individual standards under it.

• 2.NOS.A.2.a

  Skip-count forward and backwards by 2s, 5s, 10s, and 100s.

• 2.NOS.A.2.b

  Use skip-counting to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns.

01

What Students Need to Do

Students count forward and backward from any number up to 1,000. They count by 2s, 5s, 10s, and 100s in both directions. They also count equal rows or columns to find how many objects are in a small array.

02

What Mastery Looks Like

A student can count back from 402 through 400 without losing their place. They can count by 10s from 263 in either direction. Given 3 rows of 4 counters, they count 4, 8, 12 and say there are 12 counters.

03

Common Misconceptions

Students may stop at a hundred boundary or say 390 after 400 when counting back by ones. Some change only the last digit when counting by 10s. In an array, they may count the rows instead of the objects in each row.

04

How to Assess It

On an exit ticket, ask students to count back by 10s from 413 for four numbers. Draw 4 rows of 3 dots and ask them to write the numbers they say while counting each row.

1. 01

   Have students build 3 rows of 4 counters, then point to each row as they count 4, 8, 12.

2. 02

   Ask, "When you count back by 10 from 403, what number comes next, and why?"

3. 03

   Give pairs a number from 400 to 600 and a 2, 5, 10, or 100 card; write two jumps each way.

4. 04

   Mark a pretend fundraiser chart at 200, 300, 400, and 500 tickets; have students count up and back by 100s.

• 1.NOS.A.1.a

  Count forward and backwards by ones starting with any number.

• 1.NOS.A.1.b

  Skip count forward and backwards by tens.

• 1.NOS.A.1

  Count forward and backward within 120.