Maryland Math 5.NOS.B.6

5.NOS.B.6 is a cluster heading. These are the individual standards under it.

• 5.NOS.B.6.a

  Apply estimation strategies to estimate sums and differences of decimals.

• 5.NOS.B.6.b

  Use concrete models, drawings, strategies based on place value (e.g., partial sums), properties of operations and/or the inverse relationship between addition a...

• 5.NOS.B.6.c

  Use an algorithm to add and subtract decimals.

• 5.NOS.B.6.d

  Determine and explain when a strategy or algorithm is most efficient.

01

What Students Need to Do

Students estimate sums and differences of decimals to hundredths. They find exact answers using models, place-value methods, or a written algorithm, then explain why they chose that method.

02

What Mastery Looks Like

A student can estimate 4.70 − 1.86, calculate 2.84, and check by adding 2.84 + 1.86. They line up decimal points in a written algorithm and can show regrouping with a place-value drawing.

03

Common Misconceptions

Some students line up the last digits instead of the decimal points. Others think 0.4 is less than 0.36 because 4 is less than 36, or forget to regroup tenths into hundredths.

04

How to Assess It

Exit ticket: Estimate 5.20 − 2.78, then find the exact difference with a method you choose. Explain your choice in one sentence and check by adding.

1. 01

   Give pairs 1, 0.1, and 0.01 place-value disks to build 2.35 + 1.47, trade ten hundredths, and record 3.82.

2. 02

   Ask students to compare counting on and columns for 5.00 − 3.98, then defend the method they would choose.

3. 03

   Hand out expression cards (4.2 + 0.35, 3.1 − 0.48) and answer cards (4.55, 2.62); students match them and check by rounding.

4. 04

   Use $3.75 apples and $2.49 bread; students estimate the cost, calculate the total, and find the change from $10.

• 5.NOS.B.7

  Apply and extend previous understanding of multiplication and division of whole numbers to multiply and divide decimals to hundredths in context.

• 3.NOS.A.1

  Apply and extend place value understanding to whole numbers within 10,000.

• 4.NOS.E.12

  Apply and extend previous understanding of addition and subtraction of whole numbers to add and subtract fractions with like denominators.