The Chinese words 算 (suàn), 算上 (suànshang) and 算了 (suànle) can be quite easy to mix up because of their similarity. The way to deal with this is to learn the differences as clearly as possible.
算 (suàn): to sum
Starting with the simplest of these words, let's have a look at 算. When used as a verb, 算 means "to sum" or "to calculate".
我们先来看看三者中最简单的词"算"。"算"作动词，表示"合计（to sum）" 或"计算（to calculate）"。
Let's have a look at some example sentences for this meaning of 算:
wǒ yòng jìsuàn qì suànchū wǒ de kāizhī zǒng'é.
I totaled up my expenses with a calculator.
wǒ yào suàn suàn wǒ jīntiān yīgòng huāle duōshǎo qián.
I'm going to calculate how much money I've spent today.
wǒ suànle suàn, zhè cì lǚxíng yào huā dàgài yī wàn kuài rénmínbì.
I've calculated that I'll spend about ten thousand RMB on this trip.
Another meaning of 算 as a verb is "to consider", "to regard as" or "to count as". Some examples:
"算"还有另外一种意思，作动词，表示"认为（to consider as）"，"看作（to regard as）"或"视为（to count as）"，例句：
tā suàndé shàng yīgè zuòjiā.
He can be considered as an author.
zài huāyuán zǒu yī zǒu suàn bù shàng duànliàn!
Taking a walk in the garden doesn't count as exercise!
nà suàndeshang dàoqiàn ma?
Does that count as an apology?
zhè suànbuliǎo shénme.
This doesn't amount to much.
You could think of the basic, core meaning of 算 as "to calculate to be". This ties together all of the different uses of 算.
"算"的最基本、最核心的意思为"计算（to calculate to be）。这是"算"的其他所有不同用法的基础。
算上 (suànshang): to count in
The next word we'll look at is 算上. This means "to count in" or "to include". Again, you could think of this as "to include in your calculations". Some example sentences for 算上:
接下来，我们看看"算上"这一词。"算上"的意思为"把……计算在内（to count in）"或"包括（to include）"。
suàn shàng wǒ ba!
Count me in!
suàn shàng tāmen, wǒmen yīgòng yě zhǐyǒu wǔ gèrén.
Even counting them in, there's still only five of us.
suàn shàng fùjìn de cūnzi, zhège zhènzi de rénkǒu yīgòng yǒu liùqiān duō.
Including nearby villages, the population of this town is over six thousand.
One important thing to note about 算上 is that it is not the same as constructions like 算得上 (suàndeshang) and 算不上 (suànbushang). They mean "can be considered as" and "can't be considered as", respectively.
需要说明的重要的一点就是，"算上"和"算得上"、"算不上"并不相同。"算得上"的意思为"can be considered as"，"算不上"的意思则为"can't be considered as"。
算了 (suànle): forget it
This is much more colloquial. 算了 means "forget it" or "let's drop the matter". Note that it can be slightly abrupt or rude in some situations.
"算了"更加口语化，其意思为"forget it"或"let's drop the matter"。需要说明的是，在某些情况下，"算了"带有唐突无礼的意味。
Some example sentences for 算了:
wǒmen jiù suànle ba, nǐ shuō ne?
Let's just forget it, what do you think?
suànle! Wǒ shòu gòule.
Stop it! I've had enough.
yàoshi tiānqì bù hǎo jiùsuànle ba.
If the weather's not good then let's just forget it.
jìrán méiyǒu niúnǎi, zánmen jiù hē hēi kāfēi suànle.
Since there's no milk, let's just drink black coffee.
算了 has a sense of giving up or dropping one's original intentions. It's often used as a response to circumstances or people that can't be dealt with or that the speaker is no longer willing to deal with.
Translated from: chineseboost
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