Error Analysis Answer Key

About This Worksheet

This worksheet helps sixth-grade students become better at spotting and explaining mistakes in decimal calculations. Each problem already shows an incorrect answer, and students must figure out what went wrong before finding the correct result. The activity includes both multiplication and division, so students have to pay close attention to the operation as well as decimal placement. It is a strong way to move students beyond simply getting an answer and toward understanding why a calculation is correct.

What Students Practice

Students examine incorrect decimal multiplication and division problems and identify the mistake in each one. After explaining the error, they solve the problem correctly and record the accurate answer. This requires them to use place value, estimation, and operation rules all at the same time. Students also practice putting their mathematical thinking into words, which can reveal whether they truly understand the process.

Why This Matters

Error analysis is powerful because it teaches students to slow down and think about the steps behind an answer. Many decimal mistakes come from placing the decimal point incorrectly, misunderstanding the divisor, or losing track of place value. By studying incorrect work, students learn what common mistakes look like and become more likely to catch those same errors in their own work. This builds stronger independence and self-checking habits.

Teaching Tips

Ask students to explain the mistake before they recalculate the problem. If they immediately jump to solving, remind them that the goal is to understand why the original answer is wrong. Encourage them to use an estimate to decide whether an answer is reasonable before doing exact computation. During review, let students compare explanations because two students may notice the same error in slightly different ways.

Curriculum Standards

This worksheet supports CCSS.MATH.CONTENT.6.NS.B.3, which asks sixth-grade students to fluently compute with multi-digit decimals using the standard algorithm. It also strengthens the mathematical reasoning expected across the Grade 6 standards by asking students to explain errors rather than only produce answers. The activity works especially well for review, intervention, partner discussion, or a quick formative assessment.