My Math Sucks

I have lots of succulent plants which I wrote about in my previous notebook entry. I am fond of their reproduction that where a new plant can grow from a leaf. It's amazing. I remove a lot of leaves to reproduct reproduce new plants, with the number of plants increasing quickly.  But there is a problem,. I dont don't have enough space to place them, so I have to sell them in at a low price.
Yesterday, my boyfriend and I sold 4 four pots of succulent plants, the prices of for them is were 7 yuan, 7 yuan, 5 yuan and 12 yuan. The customer asked me, "How much in total?" My boyfriend calculated in his mind [1] and said, " 27 yuan." Then we went home happy with 27 yuan happilly [2]. I didn't was not aware of his mistake until the it was time to go to bed.
It's both funny and annoying. We are both bad sellers.

ps P.S.: the picture shows how a leaf grows up into a new plant.

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[1] The expression we use is "calculated in his head".  However your grammar was correct, so I have not changed your writing.

[2] The word 'happily" has only a single letter 'L'.

My Math Sucks

I have lots of succulent plants which I wrote about in a previous notebook entry. I am fond of their easy cultivation because a new plant can grow from a leaf of another plant. It's amazing. I remove a lot of leaves to begin new plants, so the number of plants increases quickly. But there is a problem. Because I don't have enough space to keep them I have to sell them for a low price.
Yesterday, my boyfriend and I sold 4 pots of succulent plants. The price for them was 7 yuan, 7 yuan, 5 yuan and 12 yuan. The customer asked me "how much for all of them?" My boyfriend calculated the amount in his head and said " 27 yuan." Then we went home happily with 27 yuan. I didn't become aware of his mistake until it was time to go to bed.
It's both funny and annoying. We are both bad sellers.

P.S. The picture shows how a leaf grows into a new plant.