Math TEKS Lesson Plan: Grade 4 Decimal Operations

Decimal errors in Grade 4 are often place-value errors disguised as calculation errors. A student can know the subtraction algorithm and still write 8.5 - 2.37 as if the 5 and 7 occupy the same place.

This complete Texas lesson addresses that problem through TEKS 4.4(A). The Texas Education Agency Grade 4 compilation states that students add and subtract whole numbers and decimals through the hundredths place using the standard algorithm. The grade introduction also says students work without calculators.

Confirm the compilation through the central TEA TEKS catalogue, then check the agency’s mathematics resources for current state guidance. Keep district pacing, materials, and local assessment expectations beside the state reference.

The plan below connects the algorithm to a place-value model, then asks students to diagnose an error before working independently. Confirm the current official standard and your district sequence before teaching.

Lesson overview

Title: Audit the class store receipt

Grade and subject: Grade 4 mathematics

TEKS: §111.6, 4.4(A), with mathematical process standards 4.1(A), 4.1(D) and 4.1(G)

Duration: 55 minutes

Materials: Place-value charts, decimal grids, fictional receipts, dry-erase boards, pencils and exit slips

Objective: Students will add and subtract decimals through hundredths with the standard algorithm and explain how place-value alignment supports an accurate solution.

Success criteria:

• I align ones, tenths and hundredths in the correct columns.
• I use the standard algorithm accurately.
• I estimate before calculating and use the estimate to check my answer.
• I can identify and explain a place-value error.

Prepare the receipt set

Create three short fictional receipts. Use prices with one and two decimal places so students must reason about equivalent notation.

Receipt A: correct total

Receipt B: misaligned digits

Receipt C: subtraction error

Receipt B makes the place-value problem visible. Receipt C reveals whether students regroup accurately after a sound setup.

Complete 55-minute sequence

Launch with reasonableness (0-6 minutes)

Display 8.50 + 2.37 = 32.20 without showing the written work.

Ask students to write one sentence: “This answer is reasonable or unreasonable because...” Do not let them calculate immediately. Collect estimates such as “a little more than 10” and connect them to the size of the addends.

Evidence: Students who accept 32.20 need work on magnitude as well as the algorithm.

Connect the model to the written algorithm (6-16 minutes)

Represent 8.50 and 2.37 on a place-value chart. Use ones, tenths and hundredths columns. Then write the vertical algorithm directly below the chart.

Think aloud:

1. The decimal point marks the boundary between ones and tenths.
2. Each digit goes in its matching place-value column.
3. 8.5 can be written as 8.50 because the added zero does not change its value.
4. Add from hundredths to ones.
5. Compare 10.87 with the estimate.

Students annotate a matching example on their own chart.

Guided error analysis (16-28 minutes)

Pairs receive Receipts B and C. For each one, they must:

• estimate the expected total or difference;
• circle the first incorrect step;
• write the numbers with correct place-value alignment;
• calculate the correct answer;
• explain the error in one sentence.

Use this sentence frame only where needed: “The ___ digit was placed in the ___ column, but it belongs in the ___ column.”

Teacher look-fors:

• Students align decimal points rather than the rightmost digits.
• Added zeros are used as place holders, not treated as new value.
• The explanation names a place value rather than saying only “they lined it up wrong.”

Guided practice (28-39 minutes)

Work through three problems, increasing the demand:

1. 12.46 + 5.30
2. 20.00 - 7.85
3. A receipt with three items: 4.75 + 2.60 + 1.89

For each problem, students show an estimate before the algorithm. Pause after setup so partners can check only the alignment. Then calculate.

Do not add a separate rule that students must always write two decimal places. The goal is correct place-value reasoning through hundredths. Equivalent notation is a support for alignment.

Independent performance (39-50 minutes)

Students complete this class-store task:

A customer buys a folder for $3.85, a set of pens for $6.40 and paper for $2.75. The customer uses a $5.00 coupon. Find the amount due. Show each algorithm and write one sentence explaining how you checked the result.

Expected total before coupon: 13.00. Expected amount due: 8.00.

Score four pieces of evidence:

Exit ticket (50-55 minutes)

Show this student’s work:

Ask students to decide whether the answer is correct, rewrite the setup if needed and explain one check. The correct difference is 6.72, so this task catches an important misconception: untidy notation does not automatically mean the arithmetic is wrong. Students should recognise that 9.4 represents 9.40 and explain why the columns work.

Support and extension

Place-value support: Give students a chart with columns labelled ones, tenths and hundredths. Fade the chart after two correct setups.

Language support: Pair the terms “tenths” and “hundredths” with a labelled model. Let students rehearse the error explanation orally before writing.

Regrouping support: Separate setup from computation. First approve the aligned problem, then let the student calculate with a base-ten or decimal-grid model.

Extension: Students design a receipt with a total of exactly $20.00 using three items, then write a coupon that leaves an amount between $11.50 and $12.50. They must prove both constraints.

What to do with the evidence

Sort student work by error type, not by total score:

• Magnitude error: estimate does not fit the numbers.
• Alignment error: digits are placed in the wrong columns.
• Regrouping error: setup is sound but calculation breaks down.
• Explanation gap: calculation is correct but reasoning is unclear.

Each group needs a different next lesson. Repeating the same mixed worksheet hides the reason students are stuck.

Copyable math TEKS planning block

Use the TEKS lesson plan guide for the full standards-to-evidence workflow and the kindergarten TEKS example for a concrete early-years model. The lesson plan template provides a reusable general structure.

To draft another Texas math lesson, create a Draft My Lesson account, select the Texas profile and include the exact student expectation, prerequisite skill, model and final evidence in your prompt. Check every number, solution and TEKS reference before using the material.