Adding Decimals visual Explanation

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Press Start Lesson to watch decimal addition take shape.

Align points → add by place value → regroup → bring the point downReady

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Build an addition

First numberSecond number

2.35 + 1.40 = 3.75

Visual model

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Tap a piece, coin, decimal point, or marker.

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Guided visual lesson

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Seven chapters · twenty-eight synchronized visual beats

Chapters

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Reliable method

Align decimal points → add each column → regroup at 10 → bring the decimal point down

Write equal place values in vertical columns.
Add zeros to empty ending places when helpful.
Begin at the smallest place value.
Exchange 10 pieces for 1 piece in the next column.
Estimate to check whether the exact sum is sensible.

Why the algorithm works

Each digit is a count of equal-sized units. The decimal point fixes the boundary between whole units and fractional units. Aligning the points therefore aligns equal units before they are combined.

Learning objectives

Explain decimal place value with concrete pieces.
Align and add decimals of unequal length.
Regroup hundredths, tenths, and ones correctly.
Verify a sum using money, a number line, and estimation.

Try these experiments

Add 0.68 and 0.57; watch two regroupings.
Add 3.4 and 0.056; observe the placeholder zeros.
Compare the exact sum with its whole-number estimate.

Question 1 of 7

Teacher tools

Open the ten-page touch whiteboard over the simulation. Draw freely, add mathematical shapes, upload an image, and keep a separate working page for each example.

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