LINE UP THE DECIMAL POINTS!

This keeps place values aligned

Step 1: Write numbers vertically with decimal points lined up

Step 2: Add zeros as placeholders if needed

Step 3: Add as you would with whole numbers

Step 4: Bring the decimal point straight down

Problem: 3.45 + 2.78

Problem: 15.6 + 3.247

Problem: 8 + 4.325

Step 1: Write numbers vertically with decimal points lined up

Step 2: Add zeros as placeholders if needed

Step 3: Subtract as you would with whole numbers (borrow if necessary)

Step 4: Bring the decimal point straight down

Problem: 8.76 − 3.42

Problem: 7.3 − 4.58

Problem: 10 − 3.764

Addition: Total, Sum, Combined, Altogether, In all

Subtraction: Difference, How much more, Left over, Remaining, Change

Problem: Sarah ran 3.75 kilometers on Monday and 4.6 kilometers on Tuesday. How many kilometers did she run in total?

Problem: A rope is 12.5 meters long. A piece 3.75 meters is cut off. How much rope is left?

✓ Always use 2 decimal places for money

✓ Include the dollar sign ($) in your answer

✓ $3.5 should be written as $3.50

Problem: Tom bought a book for $12.75 and a pen for $3.50. How much did he spend in total?

Problem: Lisa paid with a $20 bill for a toy that costs $14.85. How much change does she receive?

Problem: Mike has $50. He buys lunch for $8.75 and a movie ticket for $12.50. How much money does he have left?

Problem: 3.5 + ___ = 8.2

Problem: ___ − 2.75 = 5.6

Steps:

1. Round each decimal to nearest whole number, tenth, etc.

2. Add or subtract the rounded numbers

Example: Estimate 8.7 + 5.2

Common Benchmarks: 0, 0.25, 0.5, 0.75, 1

Round to the nearest benchmark

Example: Estimate 0.72 − 0.29

Problem: On a map:

Problem: Route A is 12.8 miles. Route B is 9.65 miles. How much shorter is Route B?

✓ ALWAYS line up decimal points vertically

✓ Add zeros as placeholders to match decimal places

✓ Bring the decimal point straight down

✓ For money, always use 2 decimal places

✓ Estimate first to check reasonableness

✓ Remember: 5 = 5.0 = 5.00 = 5.000

✓ Borrow when subtracting (just like whole numbers)

✓ Use inverse operations to find missing numbers

✓ Check your work by estimating

✓ In word problems, look for keywords

Line Up Decimals:

"Dots on dots, numbers in slots!"

Adding Zeros:

"When in doubt, zero it out!"

(Add zeros to make decimal places match)

Decimal Point Placement:

"Straight down the line, works every time!"

Money Problems:

"Two decimal places, that's the money way!"

Estimating:

"Round it quick, check your trick!"

Word Problems:

"Read with care, keywords are there!"