Math Student Help

If I am given a mole fraction of 0.54 for A and 0.23 for G for one strand of a double helix and asked to find the composition on the same strand for T, C and T+C and then the composition for all base pairs on the other strand can I do that without knowing the complete mole concentration? Do I assume that the total mole concentration is 77? HELP!

It doesn’t matter what the total mole is. If the mole fraction for A is 0.54, that means the strand is 54% A. It is 23% G. T+C is 100 - (54+23). 23% (or 0.23). For the other strand, since A pairs with T, it will be 54% T. 23% C. 23% A+G.

My daughter is in first grade and is struggling in Math already. She especially can’t understand subtraction. I’ve tried so many different ways. I think they just teach so fast and move on to the next problem too quickly for her. Any tips from other parents on what to do?

Maybe try visually, have ten straws give her 10, then take away 5 and ask her how many does she have left? Every time she gets it correct she gets a point. 3 points equals a cookie or whatever.

Minuend The number being subtracted from the subtrahend.

Subtrahend The number being subtracted.

Sum The answer in an addition problem.

I’d say multiplication, because I can multiply most numbers mentally instead of using scrap paper.

I can multiply in my head but I need paper and pencil to divide.

I’m currently taking an Algebra class but for my major I need to take calculus. I’m acing algebra, but what class do I need to take in between? Can you go from Algebra to Calculus, or is there an intermediary?

Usually they have something called ‘pre-calculus’ or some other of the ilk. It has trigonometry and other ‘tools’ for use with calculus.
It may or may not be a requisite depending on the school. Sometimes a calculus course builds from the ground up but the practice is gaining less and less popularity.

My chem homework has two questions:
1. Predict the VSEPR geometries around the N atoms in ammonia
2. Predict the shapes around the N atoms in ammonia.

I thought geometry and shape were the same thing?

No, they’re different. Water for example has two non-bonding pairs of electrons. Its shape is "bent". Ammonia (NH3) is "trigonal pyramid", and methane (CH4) is "tetrahedral", all different shapes with the same electronic configuration.

Just to be clear, "geometry" refers to the position of electron pairs in space, "shape" refers to the position of atoms.

Our roof is only 2 yrs old, and if we decide to add a second story, it seems wasteful to throw it away. Is it possible to tear it off and use it on the 2nd story addition?

I do not think you could re-use the shingles, you might possible salvage some of the decking for re-use.

How do you find the fraction and decimal for 2.5%?

when it comes to percentage, always divide it by 100.

fraction:
2.5% = 2.5 / 100 = 25 / 1000 = 1 / 40

decimal:
2.5% = 2.5 / 100 = 0.025

i cant find the button where im able to add worksheets in microsoft excel any help?

right at the bottom next to sheet1 you will see a what looks like an extra sheet
click it, and it will give you a new sheet.
you can also right click on your sheet1(or whatever you renamed it)

Shift F11 is th keyboard shortcut

You can do this in photoshop - just load each image into separate layers, and make the blending mode "difference".