1. Arlene Arva has five times as many diamonds as she has rubies.
a. Write a formula to describe this pattern, using D = number of diamonds and R = number of rubies.
Using words: Number of diamonds =
Or using letters: D =
b. If she has 4 rubies, how many diamonds does she have?
c. If she has 10 rubies, how many diamonds does she have?
d. How many rubies would she have if she has 15 diamonds?
e. Write a formula for the number of rubies, R =

2. Answer the questions below using this formula: A = B + C
a. If B = 5 and C = 2, the A =
b. If A = 10 and C = 2, then B =
c. Name any two values for B & C so that the A = 7: B = ___ & C =
d. Write a formula for B: B =

3. Formulas (equations): A = 3x and B = 5x + 1
a. As x increases, does A or B go up faster?
b. If x=0, then A =
c. If x=1 then B =

4. Formulas (equations): A = 2x and B = x2
Note: x2 means x squared, or x times x. Example: 32 = 3 * 3 = 9
a. If x = 1, then A =___ and B =
b. If x = 3, then A =___ and B =

5. The diameter of a circle is twice the radius.

The “formula” for this: Diameter = 2 (radius) or D = 2R
a. If a circle radius is 8, then the diameter is
b. If R = 3, then D =
c. If D = 20, then R =
d. If D = 100, then R =
e. Write a formula for a circle radius: R =

6. A cool thing about ALL circles is that the ratio of circumference divided by diameter equals π (pi).

So, we can write a “formula” for pi: π = C / D
We can also write it as C = π D (circumference equals pi times diameter)
a. Use 3.14 for π and if D = 20 centimeters, then C =
b. Use 3.14 for π and if D = 10 inches, then C =
c. If we round π to 3.14, and a string 18 inches long goes around the circle, what is the diameter? D =
Tip: think of simple numbers, like 10 = 2 * 5 so we know that 10/2 = 5

7. Formula: Speed = distance / time or S = D/T
Example: you travel 50 miles in 1 hour, so your average speed is 50 miles/hour. Or, you go 100 miles in 2 hours, so your average speed is 100/2 = 50 miles per hour (mph).
a. If your paper airplane travels 12 feet in 3 seconds, what is its average speed?
b. If Superman travels 100 miles in 5 seconds, what is his average speed?
c. Name any values for distance (D) and time (T) to get 4 feet per second speed.
D =___ and T =