Chapter 2-4 math help
Chapter 6
These were the most frequently missed problems...
3. What is the value of n if 6 x n=240
a. 12
b. 24
c. 36
d. 40
You can either divide by six or "reverse engineer"; that is, multiply a-d by 6 to get the right answer (d).
11. Find the estimated product and the exact product for 3 x 73.
a. 200 and 219
b. 210 and 219
c. 220 and 219
d. 300 and 219
Most students chose a. which is a decent answer, but not correct if you round 73 to 70.
15. What is the product for 4 x 937.
a. 3,748
b. 3,637
c. 3,628
d. 3,600
Many students just didn't "show their work" but guessed instead. Remember to put the big number on top!
937
x4
18. Which sentence is NOT true?
a. 83 x 12 = 12 x 83
b. 4 x (6x2) = (4x6) x 2
c. 11 x 0 x 7= 0
d. 70x900=6,300
This was tricky, but if students used my "magic trick" of counting zeros in (d) they could easily see that is the only answer. Many students chose b, but both of those equal 48. Students that worked out every single possible answer generally got this one right.
19. Use estimation. Which expression gives a product of about 4,000?
a. 527x5
b. 8 x 538
c. 426x7
d. 9x965
Most students who missed this one just "didn't do the math" on each estimation. a=2,500, b=4,000, =2,800, d.= 9,000...
20. Carl buys 3 packages of monster stickers and 2 packages of race car stickers. Each package contains 2 sheets with 32 stickers on each sheet. How many stickers does Carl buy?
a. 128
b. 192
c. 297
d. 320
There were several ways of working this one. Since there are "64" stickers in each package, you could multiply by 5. Or by 2 and 3 then add. Also, one student added 32 ten times. However the students arrived at the right answer, most of them DREW A PICTURE! Yay!
Many of the other errors involved basic multiplication errors, such as carrying over from the tens or hundreds, then adding on to the multiplication. I cannot emphasize enough the mastery required by the student in fluency of multiplication facts! I have handed out crib sheets, cheat sheets and even bought flash cards for certain students.
It is now in their hands to be completely masterful of these facts!!!
Math Concepts:
It is almost mandatory to memorize the times tables. Buy or make a set of flash cards and pull them out anytime!
My old class did this in car rides, waiting in line and other "down times" during the day.
We are missing key problems when we multiply greater numbers because our kids struggle with things like 6x8+3...
Consistent practice of math facts (with addends) was one reason our county had the highest test scores in the state!