5th GRADE MATH STUDY GUIDE – unit 1
SCA #1
NNS 5.4 I can round decimals to a given place value and round fractions (including mixed numbers) to the nearest half.
Example - Round 13.48 to the nearest tenths place. (answer 13.5)
Round 278.376 to the nearest hundreds place. (answer 300)
Round 3.746 to the nearest hundredths place. (3.75)
Rounding: the number in the place value being rounding will either stay the same or move up 1.
If the number to the right is 5 or higher it will move up, if it is 4 or lower it stays the same.
After rounding you make all the numbers after the rounded number 0 or you may leave them blank if they are on
the right side of the decimal.
NNS
5.11
I can explain how place value is related to addition and subtraction of decimals; e.g., 0.2 + 0.14; the two tenths is
added to the one tenth because they are both tenths.
Example – When adding and subtracting decimal numbers the decimal point and place values must be lined up vertically.
2.41 - 1.3 =
NNS
5.13
2.41
- 1.30
1.11
( add a zero to fill in any place value that is blank )
I can estimate the results of computations involving whole numbers, fractions and decimals, using a variety of strategies.
- When the words estimate or about are used in a question students do not need to find and exact answer.
Example – When estimating how much it cost for six cheeseburgers that are $1. 99, estimate them to be $2 a piece = about $12.
NNS 5.6 I can represent and compare numbers less than 0 by extending the number line and using familiar applications; e.g.,
temperature, owing money.
When comparing numbers on the number line, numbers to the left of zero are negative numbers. The farther left the numbers
extend, the smaller they are. Example: -10 is less than -9 because -9 is closer to zero.
Numbers to the right of zero are positive numbers. The farther to the right the numbers extend, the bigger they are. For example,
15 is bigger than 14 because 14 is closer to zero.
A negative number represents losing money or owing money, while a positive number represents gaining money. Example: If I
owe someone $5, I would represent this integer as -$5.
NNS 5.9 I can use order of operations, including use of parentheses, to simplify numerical expressions.
I can solve problems according to PEMDAS: Parentheses ( ), Exponents x2, Multiplication X and Division ÷ (from left to right),
Addition + and Subtraction - (from left to right).
Example: 5 X 2 – (3 X 2) + 4
-
Solve what is inside parentheses first. So, 3 X2 = 6.
-
Problem is now 5 X 2 – 6 + 4
-
Multiplication comes next. 5 X 2 = 10
-
Problem is now 10 – 6 + 4
-
Work addition and subtraction in order from left to right. 10 – 6 = 4.
-
4 + 4 = 8.
-
Answer = 8
NNS 5.5 I can recognize and identify perfect squares and their roots.
Example – 9 squared (or 92) is the same as 9 X 9. So, 9 squared = 81.
The root of the perfect square 81 is 9 because 9 X 9 = 81.
VOCABULARY WORDS
(The test WILL NOT consist of a vocabulary list. However, you must understand the meaning of the following words.):
difference, sum, decimal number, decimal place, decimal point, place value, estimate, about, equals, total, add, subtract
Integer -Any of the counting numbers, their opposites, and zero.
Negative Numbers - A negative number is a number that is less than zero, such as –3
Positive Numbers -. A positive number is a number that is greater than zero, such as 3.
Zero itself is neither negative nor positive.
Number Line - is a one-dimensional graph.
Estimate: Round to the given place before solving the problem.
Inverse - is the opposite. Perfect squares and square roots are the inverse of each other.
Perfect Square: A number times itself, such as 5 squared is 5 X 5, which equals 25.
Square Root: the inverse or opposite of a perfect square. The number you times by itself to get the perfect square. Example: Square
root of 25 is 5 because 5 X 5 =25
Place Value: Remember, numbers before the decimal are the whole numbers and numbers after the decimal are the decimal part.
Place values: hundreds, tens, ones, decimal point, tenths, hundredths, thousandths.
PRACTICE QUESTIONS
1)
What is 258.961 rounded to the nearest hundredth?
2) Jacob gets $15 in allowance each week. He bought a new CD from target for $9.59. How much money does Jacob have left
from his allowance? How much does he have left rounded to the nearest dollar?
3)
Jay ran a 4.781 second forty yard dash. Gabe ran a 4.44 second forty-yard dash.
What is the difference between there two times?
Who ran a faster forty-yard dash?
What are each of their times rounded to the nearest tenth?
4) One day, Derrick measured the distance between his house and his best friend’s house up the street and found that the front
doors are 197 feet apart. If derrick makes 4 trips to and from his best friend’s house a week, ABOUT how many total feet does
he have to walk between the two houses?
5)
6)
7) Amy owes her brother $5. Represent this amount as a number.
8) Use the order of operations to simplify the expression.
4 X (5+2) - 7
9) In the following problem, which operation you would perform first? Explain.
8 X (5 + 2) – 4 ÷ 2
10) What is the square root of 64?
11) What is 6 squared?
12) Perfect squares and square roots have an inverse relationship. Explain what this means.