Skills Checklist | IB Math AAHL

Skill Checklist

Track your progress across all skills in your objective. Mark your confidence level and identify areas to focus on.

5 Skills Available

Track your progress:

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Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Rounding Numbers

2 skills

Rounding rules

SL Core 1.1

There are standardized rules for how to approximate numerical values:

If the digit after the one being rounded off is LESS than 5 (0,1,2,3, or 4), we round down.
If the digit after the one being rounded off is 5 OR MORE (5,6,7,8, or 9), we round up.

1.34∣5→1.35

1.34∣4→1.34

Significant figures

SL Core 1.1

A significant figure is any digit that is not a leading or trailing zero. To round off to a number of significant figures, count off the specified number of significant figures, then round based off of rounding rules (down if the next digit is less than 5, up if the digit is 5 or more).

NOTE: Unless a question states otherwise, on IB exams, you are expected to give answers to 3 significant figures.

Scientific Notation

3 skills

Writing numbers in standard form

SL Core 1.1

Scientific notation is a useful way to write large or small numbers in a compact form. It uses powers of 10 to "condense" a lot of digits. Numbers written in scientific notation are of the form

a×10k

where 1≤a<10 and k∈Z.

Scientific notation is sometimes called "standard form."

Adding & subtracting numbers in scientific notation

SL Core 1.1

Let x=3×105,y=4×106, and suppose we want to find x+y.

Since the powers of 10 are different, we cannot simply add 3+4. Instead, we rewrite y so it is multiplying 105:

y=4×106=4×105+1=40×105

Now we can add:

x+y=3×105+40×105=43×105

Finally, we convert back to scientific form, since 43>10:

x+y=4.3×106

Basically, we took the higher power of 10 and "split" it so that it matched the smaller power of 10.

Multiplying & dividing numbers in scientific notation

SL Core 1.1

We can multiply and divide numbers in scientific form as follows:

(3×109)×(4×105)=12×1014=1.2×1015

4×1053×109=0.75×104=7.5×103

Multiplying and dividing numbers in scientific notation relies heavily on exponent rules.