Why multiply everything inside the brackets?
If you multiplied the x but left the other number alone, you have found a useful place to pause. The outside number counts copies of the whole group.
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Math lessons 56
Where did the negative sign go?
A negative sign belongs to the number next to it. Keeping that number together can prevent an almost-correct equation from turning into the wrong answer.
Try this lessonWhy can’t I add the denominators?
Before you add pieces, make sure they are the same size. The denominator names the pieces; the numerator counts how many you have.
Try this lessonScience lessons 24
Which organelle makes the cell's energy?
You said the nucleus makes the cell's energy. The instructions live in the nucleus, but the energy-making has a different address.
Try this lessonWhich way does water move through a cell membrane?
You said water rushes into the cell because the cell needs it. Water does not choose sides; it simply spreads toward the saltier solution.
Try this lessonWhere does a growing plant's mass come from?
You said the soil feeds the plant. Soil holds water and minerals, but most of the tree's wood is built from carbon in the air.
Try this lessonChemistry lessons 20
Why isn't the mass number just the neutrons?
An atom with 17 protons and 18 neutrons: is its mass number 35 or 18? And what is its charge? Work through the counting rules one blank at a time.
Try this lessonWhy does sulfur have 6 valence electrons, not 16?
Sulfur has 16 total electrons but only 6 that do chemistry. Learn where those 6 live and how the periodic table reveals them.
Try this lessonWhich is bigger: sodium or chlorine?
Sodium and chlorine sit next door in the same period, but one is much larger. Decide which, then test the down-a-group trend.
Try this lessonWriting lessons 6
Why does my teacher say my thesis is vague?
You wrote “School uniforms affect students” and the margin says “so what?”. The sentence is true, and that is exactly the problem: nobody could argue with it.
Try this lessonWhy does my paragraph feel like two paragraphs?
A reader gets to the third sentence and loses the thread. Usually that is not because the writing is hard — it is because the paragraph is quietly doing two jobs at once.
Try this lessonWhy does “because it's true” get circled?
Every sentence in the paragraph is true, and the paragraph still does not argue anything. What is missing is the sentence that links the evidence to the claim.
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