Download Chapter 4 Study Guide

Chapter 4 Study guide
*Decimal- a number that is written in a system based on multiples of 10. P. 228
*Benchmark decimals- are common decimals you can use to estimate the value of other
decimals. P. 247
*Terminating decimal- a decimal quotient with a remainder of zero. P. 255
*Repeating decimal- a decimal in which a digit or a group of digits repeats without end. P. 255
*A decimal point is used to separate the whole number and the decimal. See chart.
Thousands hundreds
tens
Ones
Decimal
tenths
hundredths Thousandths
3
4
2
1
.
5
6
7
3000.
400.
20.
1.
.
.5
.06
.007
How to say decimals:
1.
Say the whole number (three thousand four hundred twenty-one
2.
Say the decimal (and)
3.
Say the part of a whole how it appears (five hundred sixty-seven)
4.
Say the last place value (thousandths)
*Put it together (three thousand four hundred twenty-one and five hundred sixty-seven thousandths)
Translate between expanded and standard form of decimals
3.64 Standard form = expanded form 3 + .6 + .04
-Remember to place a zero behind the decimal and in front of the number to represent all
values)
3.215 = 3 + .2 + .01 + .005
place
Compare using <,>, =
-To compare decimals, line up the decimals first compare whole numbers first then move to decimal
positions.
3.12 < 2.99 because 2 is less than 3
.3339 > .3399 because .3399 has a nine before the 3 and after the decimal
1.004 > .1007 because 1. 004 has a whole number
-The zero added at the end does not affect the answer.
.37 = .370 = .3700 = .37000 the zero changes nothing when added after the decimal
Estimation
-First round the decimals to easier numbers to work with then add or subtract like normal.
.32 + 1.2278 + .15009 + 51.23
-In this case rounding to the tenths place is probably going to give a good estimation of the answer.
Below is how you would round the numbers:
.3 + 1.2 + .2 + 51.2 = 52.9 or about 53 you could also round to the whole numbers:
1 + 51 = 52 The more place values you add the closer the answer will be.
Rounding p. 250
-Look at the place value being rounded and circle it
-Look at the number to the right of the place value being rounded.
-If the number is 0-4 the rounded place value stays the same
-If the number is 5-9 the rounded place value goes up
Round to the nearest thousandth
25.3881 = 25.388
3,907.2375 = 2,907.238
Add and subtract decimals
-Line up decimals
-Add zeros so that every number has the same amount of decimals after the decimal place
-Subtract or add from right to left as you would any other problem but bring the decimal down first.
.23 + 33 + 88.4215 =
88.4215
33.0000
The whole number has a hidden decimal to the right
+ .2300
121.6515
5 – 4.27 =
5.00
-4.27
.73
Dividing
P. 280
*Dividend- the number or decimal that is being divided into equal groups.
*Divisor- the number or decimal that divides the dividend.
*Quotient- the result of the division sentence. Quotients can be whole numbers, decimals or fractions.
Common Core Textbook Review p. 297-304
Multiplying with Decimals
*This is a hundredths block.
Steps to multiplying fractions
1. Use the first decimal 0.3 Each vertical row counts as 0.10 Shade the first three vertical columns.
2. Use the second decimal 0.7 Shade 7 horizontal rows.
3. Count the DOUBLE SHADED blocks (21 blocks) The answer is 0.21
*Note: It does not make a difference if you shade the first decimal vertically or horizontally. This is also
true with fractions.
Tentative Schedule for Unit 4
October
4
4.1
Introduction to Decimals
7
8
9
10
11
4.2
4.3
4.4
4.5
4.6
Comparing, Ordering, Estimating and Rounding Decimals
Fraction Decimal Equivalencies
Adding and Subtracting Decimals
Multiplying Decimals
Long Division of Whole Numbers
14
15
16
17
4.7
Dividing Decimals
Review Lessons 4.5 and 4.7 (using models)
Review Practice Test (20 Questions Multiple Choice)
Chapter 4 Test (20 Questions Multiple Choice)