Lessons + CET Practice
175 worked lessons and every practice set, marked instantly.
₱499one payment
CET Math Review · Counting
Repeated Letters: Permutations When Some Items Look Identical
How many arrangements of MATHEMATICS? Tally the letters, put 11! on top and one factorial per repeated letter underneath — 39 916 800 ÷ 8 = 4 989 600.
This lesson is part of a NEXUS plan.
Log in if you already have a plan, or pick one below. You pay once with any QR Ph app (GCash, Maya, your bank) and the whole library unlocks straight away.
Plans
Pick a plan, pay once by QR Ph
The diagnostic exam stays free. Everything else is one payment, no subscription.
All-Access Pass
Lessons, every practice set, and a seat in the current live review batch.
₱1,499one payment
Compare every plan, including the review pack and live classes »