SME
Grade 3 Math · Problem type
Understand the whole
Use this to find the whole from one part: “This bar is 1/3. Draw the whole.”
Diagram
One part is 4 cm.
3 parts make the whole: 12 cm.
This is an example. Type your own values to start a new problem.
Parts in one whole
×
Length of one part (cm)
=
Length of the whole (cm)
Formulas
3 × 4 = 12
Parts in one whole × length of one part = length of the whole
Assumptions
•
1/3 is one of 3 equal parts of the whole.
•
Put 3 parts the same size end to end to make the whole.
Step-by-step
WE KNOW
Length of one part: 4 cm
Parts in one whole: 3
FIND
length of the whole
Step 1 · Find length of the whole
3 × 4 = ?
Parts in one whole × length of one part = length of the whole
Multiply the parts in one whole by the length of one part.
1
3
is
one
of
3
equal
parts,
so
the
whole
is
3
parts
of
4
Count by 4s, 3 times: 4, 8, 12 → 12
Length of the whole = 12 cm
Check
Put the numbers back in. Both sides should match.
3 × 4 = 12 ✓
Topic check
See what you know: 5 questions on this topic
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Main lesson
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Represent whole numbers as fractions
Use this for “How many fourths make a whole?” or 8/4 = 2.
Equal parts of an area
Use this for “Is each part one fourth of the area?”