Rational Numbers and Operations

Mrs. Lopez teaches seventh graders about adding and subtracting rational numbers, including mixed numbers, decimals, and fractions. The lesson covers rules for operations, using number lines for visualization, and solving real-world problems. Exercises reinforce understanding of concepts like borrowing in subtraction and converting between decimals and fractions.

What is the key rule to remember when subtracting rational numbers?

• Always subtract directly.

• Add the numbers as they are.

• Convert subtraction into addition.

• Ignore the negative sign.

How do you represent the sum of rational numbers on a number line?

• Draw an arrow starting from the negative number.

• Draw an arrow starting from the sum.

• Draw an arrow starting from the first number.

• Draw an arrow starting from zero.

What property allows you to change the order of addends without affecting the sum?

• Identity Property

• Associative Property

• Commutative Property

• Distributive Property

When converting a subtraction problem into addition, what must you do with the second number?

• Ignore it.

• Double it.

• Change it to its additive inverse.

• Keep it the same.

How do you handle a subtraction problem involving decimals?

• Convert decimals to fractions.

• Align the decimals and subtract directly.

• Ignore the decimal points.

• Convert subtraction into addition and align decimals.

In a practical scenario, if you owe $7 and earn $5.50, how much do you still owe?

• $1.00

• $0.50

• $2.00

• $1.50

If a car starts with 12 gallons of gas and uses 10 1/8 gallons, how much is left?

• 1 1/8 gallons

• 2 gallons

• 1 7/8 gallons

• 3 gallons

What is the position of a fish that swims 3 1/2 feet below the surface and then 5 1/4 feet deeper?

• 8 feet below

• 7 feet below

• 9 feet below

• 8 3/4 feet below

How do you find a common denominator for fractions?

• Multiply the numerators.

• Find the least common multiple of the denominators.

• Subtract the numerators.

• Add the denominators.

What is the result of adding -3 1/2 and -5 1/4?

• -8

• -8 3/4

• -9

• -7 3/4