Math Tips

September 17, 2015 at 8:15 am (MATH) (, , , , , , , )

Here are some topics we’ve been crushing in math:

  • Numbers in expanded form.  So what does this look like/mean?  Stretch out a number, look at the multiple ways a number can be represented.
    • 268,549 = 200,000+60,000+8,000+500+40+9 = (2 x 100,000)+(6 x 10,000)+(8 x 1,000)+(5 x 100)+(4 x 10)+(9 x 1) = 26 ten thousands + 85 hundreds + 49 ones

str

  • ID digits and their place value.  What’s the difference? Value = worth, while digits = the numeral in a given spot.
    • 34,701:  The digit in the ten thousands place is the numeral 4 and is worth 4,000 ones, 40 hundreds, 400 tens, or 4 thousands.
    • (25,391;   659,447;   999,581) Which five digit is worth the least?  The 5 in 999,581 is only worth 5 hundreds.

dig

  • Using number lines to round number to a given place value, but more importantly explaining why that given number is rounded to the nearest ten/hundred/etc.
    • 45,327 rounded to the nearest thousand =45,000.  How do we know this to be true?
    • Concentrate on rounding the thousands place, block out all else for now and focus on the thousands place and the place value directly behind it (hundreds).
    • This creates the number 53 (hundreds).  What do I know?  I know 53 is between 50 and 60.
      • So, I can create a number line from 50 to 60 (which represents 5,000 to 6,000)
        • Then find/mark 53 on this number line.
          • By looking at my visual, I can explain that 53 (hundreds) is closer to 50 (hundreds) by three whole jumps compared to 60 (hundreds) which is seven whole jumps away.
            • My ten thousands digit remains the same (4), I place the 50 hundreds (5,000) behind it and voila 45,000.

num

Many steps in these processes.  Now you know what your child is up against, and this is just review from third grade.  AND as I interject again, they are crushing these skills.  Hope this will help you help them once these type of problems begin to make their way home.

steps

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