Mathematics · Grades 4–8

Fraction, decimal and percent benchmarks

Compare common representations and check the whole before using a percentage.

Understand the idea

All three describe half of the same whole.

1/2 = 0.5 = 50%

Half of 18 is 9.

Divide the whole into four equal parts.

1/4 = 0.25 = 25%; 3/4 = 0.75 = 75%

3/4 of 20 = 15.

Each fifth is 20 percentage points of the whole.

1/5 = 0.2 = 20%; 2/5 = 0.4 = 40%

2/5 of 35 = 14.

Decimals need not have just one or two places.

1/8 = 0.125 = 12.5%; 3/8 = 0.375 = 37.5%

3/8 of 40 = 15.

A percent is a number of hundredths; keep the reference quantity clear.

percent = decimal × 100

0.06 = 6%, not 60%.

The old value must be nonzero; the denominator is not automatically the new value.

change % = (new − old)/old × 100

20 to 25 is a 25% increase.

Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.