These characters all look a bit similar and some of them are even conceptually related. By learning them as a group they are easier to recall.
亦 Yi4: Also, Too
Also, Too: It’s a pictogram of a person carrying something under his arms He is ALSO carrying something else.
变 Bian4: Betray, Change, Rebel, Renounce
Change, Rebel, Renounce, Betray
is a combined composite character. On top is a persons Also carrying something; beneath is a hand. The idea is that the person is going back on their oath; this idea grew into the idea of change generally. To change, alter, but also to renounce, betray.
赤 Chi4: Scarlet, Red, Bare, Naked
Scarlet, Red, Bare, Naked
It’s a picture of a naked person on top (this portion deformed/simplified to its present form) above a fire, he is naked and heating himself. The fire’s flames are red so is the naked person’s heating body.
弃 Qi4 Abandon
It’s an infant in a basket, above two hands. Is that baby for sale? It is now! It means to abandon: baby in a basket, abandoned.
允 Yun3 Allow, Permit
It’s a combined concept character of a mother above nursing an infant below; she is PERMITTING and ALLOWING it.