In preparing for a test on a set of material, is it better to study one topic at a time or to study topics mixed together? in one study,1 a sample of fourth graders were taught four equations. half of the children learned by studying repeated examples of one equation at a time, while the other half studied mixed problem sets that included examples of all four types of calculations grouped together. a day later, all the students were given a test on the material. the students in the mixed practice group had an average grade of 77, while the students in the one-at-a-time group had an average grade of 38. what is the best estimate for the difference in the average grade between fourth-grade students who study mixed problems and those who study each equation independently?

32/80  

91/140

the last one 54 doesn't go into 45. 54/100 ?

step-by-step explanation:

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.