Percent Problems 1 1 Percent Problems Grade 8

Percent Problems 1

1 Percent Problems Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • Remember that percent problems can often be solved using proportions, as described in the equation, “The part over the whole is equal to the percent over 100. ” Using this proportion, you can find either the part, the whole, or the percent, depending on what is asked in the question.

Percent Problems—Again! Price Discount Sale Price + Tax Total Cost 2

2 Percent Problems—Again! Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • Remember: Once you find the missing part, whole, or percent, you are not always finished with a percent problem. Some problems require you to add or subtract, too! • For example, when there are SALES, you may have to SUBTRACT the discount from the original price. Or, if there are TAXES, you may have to ADD the percentage back to the original price. • Read ALL the problems carefully, and make sure you are answering the question that was asked.

Which can be used to find th the “n term”? Position st 1 nd 2 rd 3 Term 3 6 9 th 4 th n ? 3

3 Which can be used to find the nth Grade 8 term? Test administrator: Before administration begins, show students the front of this card and say: • • • Look at this sequence that goes 3, 6, 9, …. The question is, “Which expression or formula can be used to find the ‘nth term’? ” Do you think it is n+3, or is the answer 3 n? Answers may vary The correct answer is B) 3 n. If you look at this pattern, it is true that you can add 3 to get the next number. For example, you would add 3 to 9 to get the 4 th number in the sequence, which is 12. BUT… the question does NOT ask what you should do to 9 to get the 4 th term. Instead, the question asks: – What could you do with a 4 to get the 4 th term? – What could you do with a 3 to get the 3 rd term? – What could you do with a 2 to get the 2 nd term? And so on. • Here, you would find the 4 th term by doing 3 times 4. Also, you could find the 3 rd term by doing 3 times 3. So, you could find the “nth term” by doing 3 times n, or 3 n.

Formula Chart • Perimeter • Circumference • Area • Surface Area • Volume 4

4 Formula Chart Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • • Many problems will require you to use the formula chart. It is separated into about three sections: Perimeter and Circumference are at the top; then comes Area, and then Volume. What’s the difference between perimeter, area and volume? Answers may vary. Repeat these phrases after me: – – – • Area covers [Students repeat: “Area covers. ”] Volume fills [Students repeat: “Volume fills. ”] Perimeter goes around. [Students repeat: “Perimeter goes around. ”] Area is in square units [Students repeat: “Area is in square units. ”] Volume is in cubic units [Students repeat: “Volume is in cubic units. ”] Perimeter is in plain units. [Students repeat: “Perimeter is in plain units. ”] In a measurement problem, ask yourself whether you must cover, fill, or go around an object to know which formula or units to use.

5 Capital “B” in “B” is the Area of the Base Area = lw Base Area = r 2 Volume = (lw)h Volume = ( r 2)h

5 Capital “B” in V=Bh* Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • • On the formula chart, Volume for a prism or cylinder is listed as “V equals capital B times h. ” Remember that the CAPITAL B does not represent one number from the picture that you can plug into this formula. Instead, CAPITAL B represents the AREA of the BASE of the prism or cylinder. For example, for the prism that looks like a box, what shape is on its Base? A rectangle How do you find the area of a rectangle? Length times width This means that you could re-write the formula for the volume of a box as, “length times width times height. ” Now look at the cylinder. What shape is on the Base of a cylinder? A circle How do you find the area of a circle? Pi times the radius squared This means that you could re-write the formula for the volume of a cylinder as, “pi, times the radius squared, times the height. ” Again, remember—CAPITAL B represents the AREA of the BASE of the prism, pyramid, cylinder or cone.

Probability 6

6 Probability Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • Look at this picture. It shows two dice, and both are showing the value “ 1. ” • If you were asked to find the probability that you would roll two die and get BOTH of them to land on “ 1, ” you would have to complete these two steps: • First, write the probability that the first die land on “ 1, ” which is 1 out of 6. • Then, write the probability that the second die also lands on “ 1, ” which is also 1 out of 6. • Finally, you must MULTIPLY these two ratios to get 1 out of 36. • Remember: ANY TIME you must find the probability that TWO things happen at the same time, you must MULTIPLY their individual probabilities together.

7 0, 0, 50, 70, 90 Avg = 42 Mode = Most

7 Averages Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • • • Look at this picture. Here, the MEAN teacher has given the student a bad AVERAGE. This is to remind you that to find the MEAN of a set of data, you simply take the average, by totaling the numbers and dividing by the number of items. Here, the MEAN teacher averaged two zeroes, a 50, a 70 and a 90 to get a 42 average. Also, you may know that the MEDIAN on a highway or a road is in the middle of the two lanes of traffic. This is to remind you that if you need the MEDIAN of a set of data, you must find the MIDDLE number. Of course, before you do this, you must make sure that the data is in ORDER (either large to small or small to large). Here, in the student’s scores, the MEDIAN would be 50. Finally, if you are asked to find the MODE of a set of data, look for the number that occurs the MOST. Recognize that MODE and MOST start with the same letters to help you remember. Here, in the student’s scores, since there are two zeroes, the MODE is 0.

Other Tips §Read §Re-Read §Underline the question §Circle important information §Draw a picture §Label pictures 8

8 Other Tips Grade 8 Test administrator: Before administration begins, show students the front of this card and say: • You are about ready to start the Math TAKS test. Here a few more test-taking strategies that could make a big difference in your performance: • First, remember that this is NOT a timed test. You have as much time as you need. So, read every question carefully, then re-read it. • Underline the question to make sure you understand what is being asked. • Circle any important information in the problem, such as numbers, labels, units, and other mathematical terms. • If you are given information about a graph or geometric figure, sketch it on your test paper. Then label on it the information provided in the question. • Or, if a figure is already provided for you, label it with the given information from the problem.