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Number Trail Grade 5 / Week 07 / Number Hunt
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Week 07 · Unlike denominators

Number Hunt

Number Hunt
// Add and subtract fractions with different denominators
⏱ about 15 min

Saturday: Number Hunt

Riley and Bennie set off with a ruler, a measuring cup and a notebook.

"Fractions hide in lots of places," says Riley, swinging his lantern.

"Rulers show halves, fourths and eighths of an inch."

"Measuring cups show 1/2 cup, 1/3 cup and 1/4 cup."

Bennie opens the notebook. "Let us find two fractions, then add them or subtract them."

Riley grins. "And check each answer with a benchmark!"

Hunt for fractions

Look around your home with a grown-up.

Find fractions on rulers, measuring cups and spoons.

Write each fraction and what it measures.

Try it: Number Hunt
Find two measuring cups or spoons with different fractions on them.
Add the two fractions.
Subtract the smaller fraction from the larger one.
Measure two small things with a ruler, to the nearest fourth or eighth inch.
Add the two lengths, and check with a benchmark.
WHAT DID YOU LEARN?
  • Read the question.
  • Tap your answer.
1/2 + 1/4 = ?
1/3 + 1/4 = ?
1/2 - 1/3 = ?
1 3/4 + 1/8 = ?
ONE MORE ROUND
  • Read the question.
  • Tap your answer.
3/4 = ?/12
Without finding the exact answer: is 5/8 + 1/4 more or less than 1?
What is the least common denominator for 1/4 and 1/10?
◇ FRACTION CHALLENGE WITH A GROWN-UP
Each of you picks a fraction from the list: 1/2, 1/3, 1/4, 1/6 or 1/8.
Add the two fractions together on paper.
Check each other with fraction strips or a benchmark.
Take turns four times. Then try subtracting.
Draw two measuring cups you found, and write their sum.
For a grown-up
This week your child added and subtracted fractions with different denominators.
They rewrite fractions with a common denominator first, like 1/2 + 1/3 = 3/6 + 2/6.
Ask them to estimate with 1/2 and 1 before they work out an answer.
A sum like 1/2 + 1/3 = 2/5 is a common mistake; 2/5 is less than 1/2.

Great hunting! Next week Donnie the Deer shows how fractions are division.

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