I've updated our "learning equations" discussion over on the Tips page, so I wanted to share it here. Generally I avoid mnemonics when it comes to equations, but I've added an example of how I'd memorize 4/3 *pi *r^3 with memory techniques at the bottom.

**How can I use memory techniques to learn equations?**

Generally, I try to avoid "memorizing" equations. Again, the goal here is to learn efficiently by giving tangible meaning to what you're learning. In the case of equations, true understanding should be achievable, so memory techniques should generally take a backseat.

That said, I do use memory techniques for specific pieces of equations I find difficult to remember. So I'd recommend trying to identify the one or two tiny things that are tripping you up, and to encode those things specifically. For example, take this equation:

*dc1/dt = Q/V1*(cin-c1) - PS/V1*(c1 - c2/lambda)*

Let's say you're struggling to remember that the lambda is under the c2. In an appropriate area of your palace, you might imagine a swan (for 2) landing on and crushing a lamb (for lambda). Or maybe the lamb's simply raising both its front legs.

I'll also use memory techniques to better recall the steps needed to reach a final equation, assuming I've already understood it and still find that sequence difficult to remember (and still believe knowing that sequence is important).

As usual, these tips represent our personal experience and should be taken with a grain of salt. Having your own learning goals, you may find it necessary to memorize full equations, and if you decide to go that route, more power to you. I just haven't found it necessary to memorize full equations for the specific courses I've taken. As an illustration, here's how I'd memorize a full equation:

Let's take the simple formula for the volume of a sphere: 4/3 *pi *r^3. I'd probably split this over three loci in an appropriate area of my palace (let's say I've devoted this palace to a section on simple geometric equations I'm required to learn):

**Locus #1:** A large sphere to encode the equation's purpose. Simple as that. Maybe it's banging into things or simply spinning in place. [I sometimes skip this step, as I've found that after a few reviews I automatically associate the loci with the relevant topic anyway.]

**Locus #2**: Since I memorize numbers using the Major System (if you're curious, see the numbers memo Q), I imagine Gordon RAMSAY (my image for 430; nothing to encode the fraction; I'll assume I'll remember it's 4/3 and not 430; if I kept forgetting that, however, I might imagine him getting slashed in the face) tasting a PIE (for pi). [Alternatively, for anyone cringing at the Major System, I could imagine a SAILBOAT (looks like a 4) being HANDCUFFED (looks like a 3) below to the locus. A PIE is balancing on the sailboat's right edge.]

**Locus #3: **I imagine a RODEO cowboy (for radius; first thing I thought of) trying to wrangle a CUBE (for cubed).

As usual, 2-3 reviews via spaced repetition should make it all stick well. This is obviously a very simple example, but it hopefully makes clear how the technique might be applied to more complicated equations. Happy memorizing!