Subtracting Mixed Numbers

Grade: 6^th

Objectives:
1) Students will subtract two mixed numbers by renaming the original fraction and give their
answer in simplest form if necessary.
2) In groups, students will work together using fraction circles to model subtraction of mixed
numbers.

Related SOLs:
6.6 The student will
a) solve problems that involve addition, subtraction, multiplication, and/or division
with fractions and mixed numbers, with and without regrouping, that include like
and unlike denominators of 12 or less , and express their answers in simplest form;
and
b) find the quotient, given a dividend expressed as a decimal through thousandths and a
divisor expressed as a decimal to thousandths with exactly one non-zero digit.

Materials: fraction circle pieces (wholes, halves, thirds, fourths, sixths, and twelfths) all on
different color paper, subtracting mixed numbers worksheet

Procedures:
(1) Introductory Activity: As students come in, have them try the problems on the board. Pass
out quiz from Friday and go over it. Talk about answers to problems on the board.
(2) Inform students that today’s topic is subtracting mixed numbers and they will be working in
groups to help them understand the concept. Break students up into pre-made groups.
There should be four groups with four to five students in each group. Give each person a
number. Explain that when their number is called it is that person’s turn to manipulate the
pieces. Reinforce the concept of working together.
(3) Guide students using fraction circles through the given problems subtracting fractions with
like denominators . Model the two then let the groups work on the remaining two problems.
Go over the group’s work.
(4) Explain that sometimes when subtracting mixed numbers we must first rename the bigger
fraction. Go over renaming of fractions with like denominators by completing two
examples. Have students complete the remaining two examples in their groups.
(5) Work two example problems that include fractions with unlike denominators . Then work
two examples involving fractions with unlike denominators and renaming. Have students
complete the additional two problems on the sheet for each section in their groups.
(6) Closure: Review steps in subtracting mixed numbers and all types of problems discussed
above. Assign homework: p.193 #10-17.

Evaluation: Thumbs up/thumbs down agreement during lesson. Student responses to questions.
Student group participation and behavior. Each student’s completed worksheet. Assigned
homework to be checked in class the following day.

Adaptations: Give struggling students more practice renaming fractions. Students are provided
with fraction circle manipulatives for hands on modeling of subtraction problems. Students have all
example problems on a worksheet.

SUBTRACTING MIXED NUMBERS
Identifying the Pieces

Fractions with LIKE denominators

Fractions with LIKE denominators with RENAMING

Fractions with LIKE denominators with RENAMING

Fractions with UNLIKE denominators

Fractions with UNLIKE denominators with RENAMING