Maryland Math 5.NOS.B.4

5.NOS.B.4 is a cluster heading. These are the individual standards under it.

• 5.NOS.B.4.a

  Apply estimation strategies to estimate products.

• 5.NOS.B.4.b

  Use computational strategies (e.g., partial products, doubling and halving) efficiently to multiply.

• 5.NOS.B.4.c

  Use a standard algorithm to multiply.

• 5.NOS.B.4.d

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

01

What Students Need to Do

Students estimate products before calculating. They multiply multi-digit whole numbers using partial products, doubling and halving, and a standard algorithm. They explain which method takes fewer steps for a given problem.

02

What Mastery Looks Like

A student can estimate 236 × 47, then find the exact product with partial products or a standard algorithm. They spot an answer that does not fit their estimate. For 25 × 48, they can use doubling and halving and explain why it saves steps.

03

Common Misconceptions

Students may forget that the tens row in a standard algorithm represents tens. Some double both factors instead of doubling one and halving the other. Others expect an estimate to match the exact answer.

04

How to Assess It

Exit ticket: Estimate 38 × 24 by rounding 38 to 40. Find the exact product with a standard algorithm and partial products, then explain which method was quicker.

1. 01

   On grid paper, draw a 23 by 14 rectangle, split its sides into tens and ones, then label and add the four partial products.

2. 02

   Write: Which takes fewer steps for 25 × 48, doubling and halving or the standard algorithm? Show both and explain your choice.

3. 03

   Deal four digit cards; make two two-digit factors, estimate, solve with a standard algorithm, and check with partial products.

4. 04

   For 24 classrooms needing 135 pencils each, estimate the total, calculate it, and explain which multiplication method takes fewer steps.

• 6.NOS.B.3

  Fluently multiply and divide multi-digit decimals to the thousandths in context.

• 4.NOS.B.3

  Fluently add and subtract multi-digit whole numbers within 1,000,000.

• 3.NOS.D.7

  Fluently add and subtract within 1,000.

• 6.NOS.B.2

  Fluently divide multi-digit numbers.