20% of 80 is 16. One fifth of eighty is sixteen: 80 ÷ 5 = 16. Decimals agree: 0.2 × 80 = 16. Because 80 = 8 × 10, take 20% of 10 (2) and multiply by eight: 2 × 8 = 16. On the same eighty, 15% of 80 is 12, 25% of 80 is 20, and 30% of 80 is 24—so the twenty-percent slice is four pounds above the fifteen-percent cut and four below a clean quarter.
Read 20% off £80 as “drop £16,” leaving £64 before delivery or tax. If the line asks for twenty percent of eighty—fee, cohort share, or reserve—the answer is 16, not sixty-four. The post-discount total only appears when the wording shifts to “off” or “after discount.”
10% of 80 is 8; doubling gives 16 again. Neighbouring bases: 20% of 70 is 14, and 20% of 90 is 18, so eighty’s fifth sits two pounds above seventy and two below ninety—steady +2 per +10 at this rate.
Eighty is double forty, so 20% of 40 (8) doubles to 16. Scale by ten: 20% of 800 is 160—same digits, one decimal shift—useful when an eighty-pound line becomes eight hundred on the same policy.
If £80 is reduced by 20%, the reduction is £16 and you pay £64 (before other charges).
Change either value below to solve another percentage-of-number question instantly.
Formula used: (percentage ÷ 100) × number
Step 1: Convert 20% → 0.2.
Step 2: Multiply: 0.2 × 80 = 16.
Full formula: (20 ÷ 100) × 80 = 16
Fifth shortcut: 80 ÷ 5 = 16. Eight tens: eight times 20% of 10 (2) → 16.
Eighty factorises as 2⁴ × 5. Removing one factor of five for twenty percent leaves 2⁴ = 16. That is the same as doubling the eighth you get from forty’s fifth—two independent stories converging on one till-friendly integer.
If you frame eighty as eight ten-pound chunks, each loses two pounds at twenty percent, and 2 × 8 = 16 total discount—another way to see the same sixteen without touching a decimal key.
Fastest: 80 ÷ 5 = 16.
From 25% of 80 = 20, subtract 5% of 80 = 4 to return to sixteen—useful if quarters anchor your head first.
Example 1: Twenty percent off an £80 gadget
The saving is £16 and you pay £64 if no other promos stack.
Example 2: Workshop materials
A £80 kit budget with 20% held for spares sets aside £16, leaving £64 for core items if finance applies the rule literally.
Example 3: Tip on an £80 dinner
A twenty-percent gratuity line is £16 on that subtotal; the “new total” only becomes £96 if you add the tip back on, not when the question asked only for the percentage of eighty.
Example 4: Tenfold row
20% of 800 is 160. If a sheet shows 16 or 1600 for that scaled cell, check the percent-to-decimal step.
20% of 80 is 16.
Multiply 80 by 0.2, divide 80 by 5, or double 10% of 80 (8 → 16).
20% off 80 is a reduction of 16, leaving 64.