# MPM1D Flavours of Numbers 2016-02-09

We talked a while today about the kinds of numbers we use. From the “smallest” set to the “largest” we had these:

Natural numbers ($\mathbb{N}$): the counting numbers 1, 2, 3, ….

Whole numbers ($\mathbb{N} \cup \{0\}$): the natural numbers and zero, 0, 1, 2, 3, …

Integers ($\mathbb{Z}$): whole numbers with a sign that is positive or negative, like …,-3, -2, -1, 0, 1, 2, 3, ….

Rational numbers ($\mathbb{Q}$): numbers that can be represented by fractions; that is, one integer divided by another integer. The denominator can’t be zero. These numbers include all decimals as well that can be written as a terminating decimal (like 2.435) or a repeating decimal (like 2.333… or 0.145145145…).

Irrational numbers ($\mathbb{\over{Q}}$): numbers that can’t be represented by fractions. This includes numbers like $\pi$ and $\sqrt{5}$.

We talked very briefly about reducing fractions, converted percentages to decimals, and BEDMAS. I’d like to see what your BEDMAS skills are like, so we’ll have a quiz tomorrow to check.

Remember that quizzes don’t count towards your final grade. They’re a way for you and me to check on your progress and understanding so that we can make decisions about how to learn and teach. You should prepare for quizzes, but you don’t need to stress about them!

Please try to remember to bring a whiteboard (dry-erase) marker tomorrow. If you want to buy one, I have them for \$1.25 for the bullet-tip, low-odour kind.