Number Sense & Operations Adding and Subtracting Decimals © 2013 Meredith S. Moody

Objective: You will be able to… Add decimals Subtract decimals © 2013 Meredith S. Moody

Place value chart Draw your own copy of this place value chart. © 2013 Meredith S. Moody

Practice writing decimals Using the place value chart to help you, write the following decimals: One and three hundredths 1.03 Fifteen and eight-hundred seventy-five thousandths 15.875 Nine tenths 0.9 © 2013 Meredith S. Moody

Comparing decimals To compare decimals, you must compare the VALUE of corresponding place values For example, 0.459 is greater than 0.01473 because four tenths is greater than zero tenths © 2013 Meredith S. Moody

Guided practice comparing decimals Compare the following decimals using <, >, or = 2.89 and 3.0918 3 ones are > 2 ones, so 3.0918 > 2.89 14.923 and 14.098 9 tenths are greater than 0 tenths, so 14.923>14.098 0.23000 and 0.23 2 tenths = 2 tenths; 3 hundredths = 3 hundredths; zeros are =, so .23000 = .23 © 2013 Meredith S. Moody

Adding decimals Step 1: Step 2: Step 3: Step 4: Step 5: Write the number with more digits (longer #) first Step 2: Write the other number beneath it; LINE UP THE DECIMALS!! Step 3: Add zeros to fill in the spaces on the shorter number Step 4: Add the digits Step 5: Bring your decimal STRAIGHT DOWN!!!!!!! © 2013 Meredith S. Moody

Guided practice 1, addition 3.85 + 2.6801 2 . 6 8 1 + 3 5 © 2013 Meredith S. Moody

Guided practice 2, addition 15.279 + 1.85 1 5 . 2 7 9 + 8 © 2013 Meredith S. Moody

Guided practice 3, addition 234.0178 + 14.201 2 3 4 . 1 7 8 + © 2013 Meredith S. Moody

You try: Addition Add the following decimals: 32.07 + 10.1204 42.1904 2.34 + 14.013 16.353 © 2013 Meredith S. Moody

Subtracting decimals Step 1: Step 2: Step 3: Step 4: Step 5: Write the number with the GREATEST VALUE first Step 2: Write the other number beneath it; LINE UP THE DECIMALS!! Step 3: Add zeros to fill in the spaces on the number with fewer digits Step 4: Subtract the digits Step 5: Bring down your decimal STRAIGHT DOWN!!!!!!! © 2013 Meredith S. Moody

Guided practice 1, subtraction 3.85 - 2.6801 3 . 8 5 - 2 6 1 9 © 2013 Meredith S. Moody

Guided practice 2, subtraction 15.279 - 1.85 1 5 . 2 7 9 - 8 3 4 © 2013 Meredith S. Moody

Guided practice 3, subtraction 234.0178 - 14.201 2 3 4 . 1 7 8 - 9 6 © 2013 Meredith S. Moody

You try: Subtraction 32.07 - 10.1204 2.34 - 14.013 21.9496 11.673 © 2013 Meredith S. Moody