Grade 5 › G5U07 Ratios

Grade 5 › G5U07 Ratios › L2
GRADE 5 · ALBERTAOUTCOME AB-G5-5N7

L2 · One relationship, four ways: ratio, fraction, decimal, percent

Learning goal

“I can write the same part-whole relationship four ways - as a ratio, a fraction, a decimal, and a percent - and move from any one form to the others.”

Percent — a part-whole ratio that compares a quantity to 100, written with the % sign: 75% means 75 out of 100.
Part-whole relationship — how one part compares to the whole it belongs to (3 of 4 equal parts).
Decimal form — the same relationship written as a decimal number (3/4 written as 0.75).
"Out of" — the words that name a part-whole count: "3 out of 4" means the part is 3 and the whole is 4.
Worked example

In a class survey, 3 out of 4 students chose soccer. Step 1: Ratio (part-to-whole, from L1): 3 : 4. Step 2: Fraction: the part over the whole: 3/4. Step 3: Decimal: 3/4 means 3 / 4, and on the number line 3/4 sits at 0.75 (three quarters of the way from 0 to 1). Bar model, in words: a bar split into 4 equal parts, 3 shaded - the shaded part is 3 : 4, 3/4, and 0.75 of the bar, all at once. Ratio table, in words: part = 3, whole = 4. Say it plainly: the numbers 3 and 4 never change. Only the writing changes.

Check yourself — explain it

Why is the decimal for 3 out of 4 equal to 0.75 and not 0.34?

Paired problem — example still visible

1 out of 2 students has a library card. Write the relationship as a ratio, a fraction, and a decimal -> 1 : 2; 1/2; 0.5

Faded completion — last step is yours

"2 out of 5 parts are shaded: fraction = 2/5, decimal = ___" -> 0.4

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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