AtlasFoundations · start here
Fractions, proportions, percentages and rounding
- Fractions, proportions, percentages and rounding
- Next: Reading the symbols (Σ, x̄, √, ², subscripts, ≥)
Fig. 1
Trypan blue viability count of chondrocytes from a cartilage biopsy (cells; blue = dead)
Each square is one cell. Tap a square to stain or unstain it.
87 of 100 cells are clear of the blue dye, so they are . That is 87% of the count, written as a .
The other 13 cells took up the dye: they are . 87% + 13% = 100%: alive and dead always make up the whole count.
87/100 = 0.87 = 87%: three ways to write the same share. The grid shows it as 87 clear squares out of 100.
- Fraction alive
- 87/100
- Decimal
- 0.87
- Alive
- 87%
- Dead
- 13%
Explorable Prose · First look
Level 1 · First look · Foundations (ext)
Say 'how many out of how many' as a fraction, a decimal and a percentage.
Move between fractions, decimals, proportions and percentages, and round as the course does: 4 dp while working, 2 dp at the end, half-up.
ext A Foundations primer: written for beginners, not from the slides.
Out of (the step you are on)
3 of 4 pizza slices eaten is 3/4; 87 of 100 cells unstained (alive) is 87/100.
87 out of 100 cells are alive: as a fraction, 87/100.