Add and Subtract Decimals

My Notes Level 1 Support Level 2 Standard Level 3 Enrichment

Today's objectives

Content Objective: I can add and subtract decimals by lining up the place values and the decimal points.

Language Objective: I can explain my steps using the words decimal, place value, tenths, hundredths, and annex zeros.

📖 See Learn It for the explanation and worked examples, and the Vocab tab for the words. These are your notes to fill in and keep.

✏️ Fill in each blank as we go. Use the Word Bank to help you.

📚 Word Bank — fill each blank with the best word

👆 Tap any word to see what it means and a picture.

Level 3: try the blanks from memory first, then check the bank.

1A number that uses a point to show a value less than one whole is a .
2The value a digit has based on its position in a number is its .
3The first place to the right of the decimal point is the place.
4The second place to the right of the decimal point is the place.
5Writing extra zeros at the end of a decimal so the places line up is called .

Write About the Math Guided ESOL writing

Use the support level you need. Every level answers the same math question.

1. Understand the Question

explain

When you added 128.75 and 46.8, how did you handle 46.8 having fewer decimal places, and when did you need to regroup?

Your job: Answer the question. Use math evidence. Explain how the evidence proves your answer.Responde la pregunta. Usa evidencia matemática. Explica cómo la evidencia demuestra tu respuesta.

2. Plan Your Math Words

Check at least two words you will use.

Decimal — A number with a dot that shows a part between whole numbers.Decimal — Un número con un punto que muestra una parte entre números enteros. Place value — What a digit is worth based on where it sits in a number.Valor posicional — Lo que vale un dígito según el lugar que ocupa en el número. Tenths — The first spot after the decimal point. It shows parts out of 10.Décimas — El primer lugar después del punto decimal. Muestra partes de 10. Hundredths — The second spot after the decimal point. It shows parts out of 100.Centésimas — El segundo lugar después del punto decimal. Muestra partes de 100. Annex zeros — Adding zeros at the end of a decimal so numbers line up evenly.Agregar ceros — Agregar ceros al final de un decimal para que los números se alineen.

Say it first: Say your idea to a partner or quietly to yourself before you write.Di tu idea a un compañero o en voz baja antes de escribir.

I annexed a zero to write 46.8 as ___ so the place values matched.Agregué un cero para escribir 46.8 como ___ para que los valores posicionales coincidieran.

3. Build Your Explanation

Model the parts: This model shows the parts of an explanation. It does not answer your writing question.

Claim: Lining up the decimal points keeps each place value matched.

Evidence: Students explain that aligning decimal points lines up matching place values (tenths under tenths, hundredths under hundredths) so the addition and subtraction are correct.

Reasoning: This evidence connects the definition of decimal to the mathematical claim.

Start

Most language support

Complete the frames. Use the word bank.Completa las oraciones. Usa el banco de palabras.

I annexed a zero to write 46.8 as ___ so the place values matched.Agregué un cero para escribir 46.8 como ___ para que los valores posicionales coincidieran.
I had to regroup when ___.Tuve que reagrupar cuando ___.

Build

Some language support

Write two connected sentences. Use because, so, or but.Escribe dos oraciones conectadas. Usa porque, entonces o pero.

My claim is ___.Mi afirmación es ___.
I know because ___.Lo sé porque ___.
So ___.Entonces ___.

Explain

Light language support

Write a claim, give math evidence, and explain your reasoning.Escribe una afirmación, da evidencia matemática y explica tu razonamiento.

My claim is ___.Mi afirmación es ___.
My math evidence is ___.Mi evidencia matemática es ___.
This proves ___ because ___.Esto demuestra ___ porque ___.

4. Check Your Explanation

I answered the question.Respondí la pregunta. I used math evidence: numbers, an equation, a model, or a comparison.Usé evidencia matemática: números, una ecuación, un modelo o una comparación. I explained how the evidence proves my answer.Expliqué cómo la evidencia demuestra mi respuesta. I used at least two math words.Usé por lo menos dos palabras matemáticas. I reread complete sentences and punctuation.Volví a leer mis oraciones completas y la puntuación.