1) The document is a lesson plan for a 5th grade math class on multiplying and dividing decimals. 2) It begins with introducing the topics through videos and definitions. Students will learn to multiply decimals by multiplying the whole numbers and counting decimal places, and to divide decimals by estimating, moving decimals, and dividing normally. 3) Examples are provided for multiplying 3.1 x 5.06 and dividing 3.6 / 0.45 to demonstrate the procedures. Additional practice activities and supplemental reading are included at the end.

1. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
1 de 6
Área: Math Asignatura: Math Curso: 5
th th
Fecha: August 20 -26 Periodo III Nº Horas: 5hr Semana: 7
Docente: Gerardo Núñez Coronado
Tema: MULTIPLY AND DIVIDE DECIMALS
Indicador Solve decimals exercises using multiplication and division procedure.
de Logro
Exploración
Contextualización
WATCH THE VIDEO: http://www.youtube.com/watch?v=dcOOYtiGQJk. DIVIDE DECIMALS
http://www.youtube.com/watch?v=zEHbLRHxQpE&feature=relmfu MULTIPLY DECIMALS
Conceptualización
MULTIPLYING DECIMALS
To multiply decimals, first just multiply the numbers as if they were whole
numbers. (Don't line up the decimal points!)
EMOCIÓN
Then count the total number of places to the right of the decimal point in BOTH
numbers you're multiplying. Let's call this number n. In your answer, start from
the right and move n places to the left, and put a decimal point.
Example:
Multiply 3.1 × 5.06.
Step 1: Multiply the numbers, ignoring the decimal point.
Step 2: In 3.1, there is 1 place to the right of the decimal point. In 5.06, there
are 2. So, since 1 + 2 = 3, move in 3 decimal places from the right in your
answer.

2. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
2 de 6
DIVIDING WITH DECIMALS
Dividing with decimals is a bit more difficult. These days, most teachers don't
mind much if you use a calculator. But it's good to know how to do it yourself,
too, and you always need to be good at estimating the answer, so you can
make sure the calculator's answer is reasonable.
Recall that in the problem x ÷ y = z, also written
x is called the dividend, y is the divisor, and z is the quotient.
Step 1: Estimate the answer by rounding. You'll use this estimate to check
your answer later.
Step 2: If the divisor is not a whole number, then move the decimal
place n places to the right to make it a whole number. Then move the decimal
place in the dividend the same number of places to the right (adding some
extra zeros if necessary.)
Step 3: Divide as usual. If the divisor doesn't go in evenly, add zeros to the
right of the dividend and keep dividing until you get a 0 remainder, or until a
repeating pattern shows up.
Step 4: Put the decimal point in the quotient directly above where the decimal
point now is in the dividend.
Step 5: Check your answer against your estimate to see if it's reasonable.
Example:
Divide.
Step 1: Since the divisor is greater than the dividend, we will get an answer
less than 1. Since 0.45 is about one tenth as big as 3.6, we expect an answer
close to 0.1.
Step 2: The divisor is not a whole number, so move the decimal point one
place to the right to make it a whole number. Move the decimal point in the
dividend one place to the right also.

3. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
3 de 6
Step 3: Divide normally, adding extra zeros to the right of 4.5 when you run
out.
Step 4: Put the decimal point in the quotient directly above the decimal point
in the dividend.
We get 0.125.
Step 5: Compare with your initial estimate. 0.125 is close to 0.1, so we're
good!
Action Rule Example
Multiply by Move the whole number one place 2.45 x 10 = 24.5
10 value to the left
Multiply by Move the whole number two place 2.45 x 100 =
100 values to the left 245
Multiply by Move the whole number three place 2.45 x 1000 =
1000 values to the left 2450
Divide by 10 Move the whole number one place 46.7 ÷ 10 =
value to the right 4.67
Divide by Move the whole number two place 46.7 ÷ 100 =

4. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
4 de 6
100 values to the right 0.467
Divide by Move the whole number three place 46.7 ÷ 1000 =
1000 values to the right 0.0467
Producción
ACTIVITY
Modelación
MULTIPLY
ACCIÓN

5. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
5 de 6
Workshop

6. Corporación Educativa
Colegio Internacional Cartagena
CLASE
Versión 01-11 Código FO-DC-01 Página
6 de 6
Lectura Complementaria:
http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-power-of-ten
http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-one-digit-whole-number
http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-multi-digit-whole-number
http://www.ixl.com/math/grade-5/divide-by-powers-of-ten
http://www.ixl.com/math/grade-5/division-with-decimal-quotients
Bibliografía
http://www.harcourtschool.com
http://www.ixl.com