Math Trailblazers Homework Help

Math Trailblazers Homework Help-Fourth Grade
Unit 7
Dear fourth grade parents,
Thank you so much for coming to this page to find out more about the math your child is
bringing home. Every page that your child could bring home is listed in this chart. Do not expect your
child to bring every page home. Often a teacher will note that the student already has a healthy
command of a skill, making assignment of homework unnecessary. At other times the teacher may
have a different assignment that (s)he feels is more appropriate.
To use these pages, find the Unit and Lesson numbers on the bottom of your child’s assignment
page or textbook and then click on the corresponding blue link in the table. You will find information
about the skills being practiced and occasionally extra notes will provide background information or
tips on how to extend the activity to make it more or less challenging.
Click links
in this column
Activity
Unit 7 Background Info
Unit 7 DAB p.85
Memorizing multiplication facts
Unit 7 DAB p.86
Estimation
Unit 7 DAB p.87
Large number place value
Unit 7 DAB p.88
Subtracting small amounts and convenient numbers
Unit 7 page 189
Place value with large numbers of acres
Unit 7 pages 195-196
Relating exponents to real-life situations
Unit 7 pages 199-200
Working with large numbers
Unit 7 pages 205-206
Finding 10% of different amounts
Unit 7 pages 209-210
Rounding, adding and subtracting large numbers
To read the small pages more easily, set the image size to 200%.
Please remember that skills in our Trailblazers program are repeated many times during the year. If
your child is struggling with a skill in Unit One it should not be as much of a concern as if your child
continues to struggle with the same skill when you see it reviewed near the end of the book.
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Fourth Grade - Unit 7 – Homework Help
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Unit 7 Background Information for Student Guide pages 189, 195-196, 199-200, 205-206 and
209-210. Students use rules of divisibility in many activities in this unit.
In case it has been a few years since you last used divisibility rules, here they are…
2 - all even numbers are evenly divisible by 2.
3 – if the sum of the digits is evenly divisible by three then the number is also.
6 – if a number follows both rules for two and three, then it is divisible by six.
5 – numbers ending with 0 or 5 are evenly divisible by five.
10 – numbers ending with 0 are evenly divisible by ten.
9 – if the sum of the digits is evenly divisible by nine then the number is divisible by nine.
Students will also use both the traditional and partial products methods to multiply two digit
by two digit numbers. Here is a comparison of the two methods.
Standard and Partial Products Multiplication
Standard
Partial
Students have been introduced to both the standard
Algorithm
Product
Algorithm and also the partial products algorithm. Different
4
48
48
kids prefer different algorithms. The partial products
x6
x6
method has kids multiply 6x8 and write the product. Then
48
288
the child multiplies 6x40 (the four in the tens column) to get
240
240. The two products are finally added together.
288
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Fourth Grade - Unit 7 – Homework Help
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Memorizing Multiplication Facts
The last six facts are usually the hardest for children.
Again remind them to work on them one at a time.
When he or she has learned one, then it is time to work
on the next one.
Order of Operations
Adults have agreed to calculate multiplication and
division before addition and subtraction (just so
everyone is doing the calculation the same way).
4+3X2=14 when the addition is done first. When order
of operations is employed, the multiplication occurs
first and the four is added to make ten. Please be
aware that some calculators automatically use order of
operations and other calculators do not.
Back to Index
Divisibility Rules
In case it has been a few years since you last used
divisibility rules, here they are…
2 - all even numbers are evenly divisible by 2.
3 – if the sum of the digits is evenly divisible by
three then the number is also.
6 – if a number follows both rules for two and
three, then it is divisible by six.
5 – numbers ending with 0 or 5 are evenly
divisible by five.
10 – numbers ending with 0 are evenly divisible
by ten.
9 – if the sum of the digits is evenly divisible by
nine then the number is divisible by nine.
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Fourth Grade - Unit 7 – Homework Help
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Partial Products Multiplication
Students have been introduced to both the standard
algorithm and also the partial products algorithm.
Different kids prefer different algorithms. The partial
products method has the kids multiply 6x8 and write the
product. Then the child multiplies 6x40 (the four in the
tens column) to get 240. The two products are then
added together.
Back to Index
Solving Problems Using Multiplication
Students may use the partial products algorithm
(calculation pattern) or the standard algorithm with
these questions. It is important that they know how
which ever algorithm they choose works.
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Fourth Grade - Unit 7 – Homework Help
Q 11-12 Practice multiplying with numbers
from a story problem.
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Unit 7 Page 189
Q 1-5 The divisibility rules on the previous
page should help. To check yourself, 3288
and 9036 are the only numbers evenly
divisible by 2, 3, 6 and 9.
Q 6 The numbers marked for multiples of 10
form one column. The multiples of five
repeat the 10 column but also have a
separate column of numbers ending in five..
Q 7-10 Here are the equations with
parentheses which are not required but
emphasize the order of operations.
(6x7) – (8x4)
1 + (48÷8)
4 + (7x8)
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Unit 7 Page 205-206
Q 1-6 This is a mixture of multiplication and
addition problems. It is important for
students to recognize that when equal size
groups are repeated they can multiply.
When the groups are different sizes, the
only choice is to add.
Q 7 The word “about” in this question should
help the child recognize that an estimate
is ok. Some may estimate 20 -10 = 10,000.
Others may estimate 20-14 = 6,000. The
estimate they choose gives a hint of the
calculation skills the child is comfortable
with.
Q 8-13 Many children will have greater
difficulty locating the correct numbers on
the data table than performing the
correct calculations on those numbers.
(4x7) – (24÷6)
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Unit 7 Page 195-196
Q 1-13 In each case the significant digits can
be multiplied and the correct number of
zeros added afterward.
Q 14-20 Practice multiplying the significant
digits and adding zeros with story
problems.
Q 21-29 Fill in the missing number using logic
rather than a calculator.
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Unit 7 Page 199-200
Q 1-3 These provide additional practice where
the significant digits can be multiplied and
the correct number of zeros added
afterward.
Q 4-6 Practice multiplying the significant digits
and adding zeros with story problems.
Q 7-9 Students are asked to fill in the missing
numbers in multiplication calculations using
the partial products method. (see the
previous page for a review of the partial
products method.)
Q 10 These calculations can be completed with
the partial product method or the
standard algorithm.
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Fourth Grade - Unit 7 – Homework Help
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Unit 7 Page 209-210
Q 1-10 These provide additional practice
where the significant digits can be
multiplied and the correct number of
zeros added afterward.
Q 12-14 Some convenient numbers could be
40 x 8
75 x 4
70 x 7
Q 15 It is possible to multiply 70 x 7 and then
subtract seven from that product.
Some convenient numbers could be
Q 16 60 x 30 or 60 x 35
Q 17 50 x 80
Q 18 300 x 70
Q 19 500 x 90
Q 20-24 Practice multiplying with numbers
from a story problem.
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Fourth Grade - Unit 7 – Homework Help