add and subtract rationals

What is the first step when adding and subtracting decimals?

• Line up the numbers
• Line up the decimals
• Add or subtract like normal
• Add in placeholders

3.75 - 4.23

-2.37 + -5.72

-4.63 - (-7.95)

-5.7 + 0.9

• 2.1
• -4.8
• -8.3
• -10.7

-6.8 + (-3.3)

• -10.1

• -7.52

• -2.6

• -17.5

6.4 + (-3.4)

• -4.2

• 1.8

• -3.5

• 3

-3.9 + (-4.3)

• -8

• -8.2

• -2.9

• -9.2

7.6 - (-6.5)

• 11.8
• 10
• 16.3
• 14.1

- 2.09 - 15.271

• -17.361
• 13.181
• 17.361
• -13.181