The rectangle below represents one whole. What decimal is represented by the shaded area?
This rectangle represents one whole. To find the decimal for the shaded area, we first need to find out how many pieces the whole is broken into. We can start counting: one, two, three, four, five, six, seven, eight, nine, 10. Our whole is broken into tenths. Nine out of the 10 are shaded. As a fraction, we write that nine over 10 — nine tenths.
In our place value system, we have the ones and then a decimal and then the tenths place. Since this image tells us we have nine tenths, we put a nine in the tenths place. We have zero whole numbers. We don’t have a whole. So a zero goes in the ones place.
The rectangle represents nine tenths. And as a decimal, we write that 0.9 — nine tenths.