Problem
Reasoning · Grade 3-2 Applying Fractions
Check condition A (improper fraction) for each
Only 12/5, 23/9, 19/4 are improper; the mixed numbers drop out.
An improper fraction is one where the top is at least the bottom; a mixed number is a different form and a proper fraction is smaller than one whole.
3.NF.A.1Make A Systematic ListCheck condition B (denominator divisible by 3)
Denominators divisible by 3: 8/12, 23/9, 3 1/6.
Checking 'divisible by 3' is just recalling the multiples of 3 — 6, 9, 12 are all in the times-three list.
3.OA.C.7Make A Systematic ListCheck condition C (greater than 5/2)
Past 5/2 = 2.5: 2 4/7, 23/9, 19/4, 3 1/6.
Turning each fraction into 'about how many wholes' lets me line them up against 2 1/2; note 12/5=2.4 just misses.
3.NF.A.3Make A Systematic ListPlace each fraction in its region
Meeting all three, 23/9 takes the centre.
Each fraction's list of true conditions names its exact slot; the one fraction true for all three sits in the very middle.
3.NF.A.1Draw A Venn DiagramThe list of conditions each fraction satisfies names its exact region, and the fraction satisfying all three sits in the very middle.
Why?
Every fraction either meets a condition or does not, so its answers to the three questions pin it to one region and no other.
Why?
The regions cover every fraction and never overlap, so each fraction is placed once and the diagram accounts for them all.
Make a quick yes/no checklist for each fraction against the three rules, and the Venn diagram practically fills itself in!
- Check condition A (improper fraction) for each
- Check condition B (denominator divisible by 3)
- Check condition C (greater than 5/2)
- Place each fraction in its region