No worries then.....Here are the "simple math numbers"I hope the...

No worries then.....
Here are the "simple math numbers"
I hope the numbers can explain what my words could not.

Without dividend
80K income tax bracket.
$45,001 – $120,000 - $5,092 plus 32.5 cents for each $1 over $45,000

The first number $5,092 is a shortcut total for all the tax brackets below.
eg. $45,000-$18,200 = 26800
$26800 * 0.19 = $5092

On 80K then.
$80000 - $45000 = $35000 <- Amount over $45,000
$35000 * 0.325 = $11375 <- 32.5% tax on amount over $45,000
$11375 + $5092 = $16467 <- Add shortcut number for tax bracket plus calculated marginal tax.
$80000 * 0.02 = $1600 <- 2% medicare on entire taxable income
LMITO $1080 <- LMITO tax offset

$16467 normal total tax on income ( excl medicare )
$16467 + $1600 - $1080 = $16987 ( including medicare and LMITO )
$16987 / $80000 = 21,23% effective tax ..... eg the tax you actually pay and is actually liable for.

With dividend

$80,000 + $100 = $80100 <- Grossed up dividend is added to total taxable income... just like any other income
$80100 - $45000 = $35100 <- Amount over $45,000
$35100 * 0.325 = $11407.5 <- 32.5% tax on amount over $45,000
$11407.5 + $5092 = $16499.5 <- Add shortcut number for tax bracket plus calculated marginal tax.
$80100 * 0.02 = $1602 <- 2% medicare on entire taxable income
LMITO $1080 <- LMITO tax offset
Franking credit $30 <- Tax witheld credit.... just like any other tax withheld credit, interest, paye

$16499.5 normal total tax on income ( excl medicare )
$16499.5 + $1602 - $1080 - $30 = $16991.5 ( including medicare and LMITO and Franking credit offset )
$16991.5 / $80100 = 21.21% effective tax ..... eg the tax you actually pay and is actually liable for.

Difference in tax paid between the two assesments? $4.5
You paid $4.5 more tax for that extra $100 income out of pocket ( or $30 tax withheld + $4.5 out of pocket = $34.5 total tax )
At face value you will think that means you paid 34.5% tax on the $100.

Effective tax rate is the amount you actually pay across your entire income.
That $100 is not special... is it the first $100 of income on which no tax is paid? or the last $100 on which 34.5% is paid?
The answer is neither.... you are taxed on the total taxable amount using the progressive tax table calculations to get to the effective tax rate.
The calcuations make it seem like you are taxed 34.5% but on average you pay only 21.21% on any given $100....including your grossed up $100 dividend.

On $80100 * 0.2121285892634207 = $16991.5 ...... this is the tax payable..

Hope that all makes sense now, best of luck.