Let's look again at the amount of money spent. They bought $15 game tokens and 3 admission tickets. If t is the cost of one admission ticket, as given, then the total money they spent can be written as:
$15 + 3 • t
making the statement a) false.
If the admission ticket costs $2.50, then, using the expression above, they spent:
$15 + 3 • $2.50
$15 + $7.50
$22.50
making the statement b) true.
From the table, we see that number of feet is always three times the number of yards.
So, if we label the number of yards with y and number of feet with f, we get:
f = 3y
which means that the number of feet in y yards is 3y.
When using decimal numbers we should know that the digit before the decimal point is integer and the digits after the point are decimals.
When adding two numbers, one of which isn't decimal number, sometimes it's helpful to write it in that manner. In this case, we could write 7 as 7.0.
Now, adding these two numbers should be easier:
7.0 + 0.8 = 7.8
Note that we simply add up decimal numbers and integers independently.
Here, it's important to remember one of the key features of multiplication; any number multiplied with one equals to that same number. It doesn't matter whether that number is integer, decimal number, a fraction or an expression.
So, in this case, we have:
8.3 • 1 = 8.3
We can write expressions for both girls. Samantha ran five miles each day for seven days, so her distance is:
S = 5 • 7 = 35
Mariska, on the other hand, ran seven miles each day for five days, meaning that her distance is:
M = 7 • 5 = 35
So, this means that they ran the same distance, but let us explain why. Another important feature of multiplication is that if you change the order of the numbers multiplied, you still get the same value. So, if we write:
a • b = c
then:
b • a = c
which was the case in this question (5 • 7 = 7 • 5).
Let's define the number of balls on the playground as b. Then, one more ball than that would be b+1.
Let's define the number of cookies in the jar as c. Then, three more cookies than that would be c+3.
Let's define the number of the questions on the first test as q. Then, twelve fewer then this would be q-12.
Let's define the cost of the shirt as s. Then, eight dollars more then this would be s+8.
Let's define number of drinks on the tray as d. Then, eight times as much would be 8•d.
Let's define Yumi's pay as y. Then, five dollars less would be y-5.
Let's define the number of students in math class as m. Then, half as many would be m • 1/2 = m/2
Let's define Emily's age as e. Then, third of her age would be e • 1/3 = e/3.
Let's define minutes spent exercising as x. Then, ten times this would be 10•x.
So, Spencer bought three books of stamps and spent $4.50 on mailing a package. The total amount Spencer spent at the post office is the amount spent on the books plus mailing of the package. If we mark the price of one book as b, since he bought three books, he spent 3•b. So, the total amount he spent in the post office is:
3•b + $4.50.
