Maryland Math 1.NOS.D.9

1.NOS.D.9 is a cluster heading. These are the individual standards under it.

• 1.NOS.D.9.a

  Use the count on and count back strategies to add and subtract (e.g., 4 + 1, 7 – 2, etc.).

• 1.NOS.D.9.b

  Use the make ten strategy to add and subtract with combinations of 10 (e.g., 7 + 3, 6 + 4, 10 – 3, 10 – 6, etc.).

• 1.NOS.D.9.c

  Use the ten more and ten less strategies to add and subtract (including those with a difference of 10).

• 1.NOS.D.9.d

  Use the doubles to add and subtract (e.g., 6 + 6 = 12, 14 – 7 = 7, etc.)

01

What Students Need to Do

Students answer addition and subtraction facts within 20 from memory or work them out quickly. They count on or back, make ten, use ten more or ten less, and use doubles.

02

What Mastery Looks Like

A student solves 8 + 2, 16 - 10, 6 + 6, and 14 - 7 without counting every object. They can explain that 7 + 7 = 14 helps them solve 14 - 7.

03

Common Misconceptions

Some students count from 1 for 8 + 2 instead of starting at 8. Others count 8 as the first step, subtract 1 instead of 10 in 16 - 10, or miss how doubles help with subtraction.

04

How to Assess It

Give an exit ticket with 9 - 2, 8 + 2, 16 - 10, 6 + 6, and 14 - 7. Ask students to solve each and show how they found one answer.

1. 01

   Put 8 counters on a ten-frame, add 2, then remove 2 and record both number sentences.

2. 02

   Ask partners, 'How does 7 + 7 help you solve 14 - 7?' Have them draw a picture and explain.

3. 03

   Play fact-flip: turn over two number cards, add them, then say a related subtraction fact.

4. 04

   Show a pack of 10 pencils and 6 loose pencils; ask how many remain if the pack is taken away.

• K.AT.A.2

  Solve addition and subtraction problems in context (add to, take from, put together/take apart) within 10 and represent by using objects, drawings, and/or equat...

• 2.NOS.B.6

  Recall or quickly derive addition and subtraction facts within 20.

• 3.NOS.E.9

  Recall or quickly derive multiplication and division facts within 100 (e.g., factors less than or equal to 10 and quotients less than or equal to 10).

• 4.NOS.C.7

  Recall or quickly derive multiplication and division facts within 100 (e.g., factors less than or equal to 10 and quotients less than are equal to 10).