Adding numbers under the root sign H

"The Root Addition Error"

Number & Proportion

Adding the percentage instead of multiplying

"The Add-On Error"

Number & Proportion

Confusing HCF and LCM

"The HCF-LCM Swap"

Number & Proportion

Dividing by one ratio part instead of the total

"The Part-Total Mixup"

Number & Proportion

Having A greater than or equal to 10

"The Ten Trap"

Number & Proportion

Moving the decimal point the wrong way

"The Backwards Shift"

Number & Proportion

Multiplying indices instead of adding when multiplying powers

"The Power Multiplier"

Number & Proportion

Using simple interest formula for compound interest

"The Simple Mistake"

Number & Proportion

Using the wrong inequality sign for upper bound H

"The Inequality Slip"

Number & Proportion

Applying index laws to different bases

"The Base Blunder"

Number & Proportion

Dividing by the new value instead of the original

"The Denominator Disaster"

Number & Proportion

Dividing numerator and denominator by different numbers

"The Unequal Split"

Number & Proportion

Giving shares to the wrong people

"The Swap Error"

Number & Proportion

Not fully simplifying a surd H

"The Partial Simplify"

Number & Proportion

Thinking 1 is a prime number

"The One Error"

Number & Proportion

Using 1 + r instead of 1 - r for depreciation

"The Depreciation Direction"

Number & Proportion

Using wrong bounds for subtraction H

"The Subtraction Swap"

Number & Proportion

Using wrong sign for small numbers

"The Sign Slip"

Number & Proportion

Finding percentage of final amount for reverse problems

"The Backwards Blunder"

Number & Proportion

Forgetting to convert percentage to decimal

"The Percentage Slip"

Number & Proportion

Getting the ratio the wrong way round

"The Flip"

Number & Proportion

Leaving a surd in the denominator H

"The Forgotten Rationalise"

Number & Proportion

Not adjusting after calculation

"The Unadjusted Answer"

Number & Proportion

Thinking negative index gives negative answer H

"The Negative Confusion"

Number & Proportion

Thinking percentage means out of 100 literally

"The Literal Hundred"

Number & Proportion

Treating truncation the same as rounding H

"The Truncation Trap"

Number & Proportion

Writing prime factorisation without index notation

"The Index Omission"

Number & Proportion

Adding/subtracting wrong amount for bounds H

"The Half-Step Slip"

Number & Proportion

Finding LCM by just multiplying the two numbers

"The Multiply Mistake"

Number & Proportion

Multiplying base by fraction for fractional indices H

"The Fraction Fumble"

Number & Proportion

Subtracting interest to find original amount

"The Reverse Mistake"

Number & Proportion