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Students in grade
two struggle to understand place value and are unable to compute correctly.
Ideas for Instruction
v
Students need to
get adequate practice representing tens and ones.
v
Students need to
connect the concept of grouping by tens with the procedure of recording numbers
founded on the base-ten number system. Children need to view ‘ten’ as both one
group of ten and ten ones.
v
In order for
students to acquire necessary conceptual skills for understanding place value,
students should count objects first by ones, then group objects by tens, checking
to see that the quantity remains the same, and finally grouping by tens with
ones “left over.”
v
Manipulatives,
such as connecting cubes, connecting links, sticks that can be banded, and
counters that fit in a cup can be used to model two-digit numbers.
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The number Thirty
- two can be presented as:
·
Thirty-two separate counters
·
Three groups of 10 counters and 2 single ones
·
Two groups of 10 counters and 12 single ones
·
One group of 10
counters and 22 single ones
·
Post a hundreds
chart in a prominent place in the classroom and put an individual copy on each
student’s desk. Ask students to look for patterns they notice on the
chart.
v
Post a hundreds
chart in a prominent place in the classroom and put an individual copy on each
student’s desk. Ask students to look for patterns they notice on the
chart.
v
Create puzzles
out of hundreds charts. Ask students to cut charts apart n different
ways, and put them back together, explaining how they knew where each piece
went.
v
Play Make
100. Each student tosses a pair of number cubes, takes that number of
counters, and keeps a record of the sums tossed. After the twelfth turn,
students determine how close they are to one hundred.
v
Play Get to
Zero. This game is the reverse of Get to 100. They begin with 9
ten-unit counters and remove the number tossed from 90 (instead of 100).
At each turn, students record how many tens and how many ones they have.
Play continues for 10 turns.
v
Introduce
computation with an expression that allows for a variety of ways to solve it.
v
Ask students to
figure out the sum for “the double of 28.” After they have done so, ask them to
share their strategies while you record them symbolically.
o I knew that 20 +
20 equaled 40 and that 8 + 8 equaled 16. And 40 + 16 equals 56.
o I knew that 28 +
20 equals 48. Then I just counted on 8 more to get 56.
o I knew that 30
+30 equals 60. Each 30 is 2 more than the 28, so I had to think 4 less
than 60. That’s 56.
v
Before teaching
the traditional algorithm, begin with models, move to pictorial
representations, and use symbols only when it’s clear that students understand
that 16 ones is the same as 1 ten in the tens place with the remaining ones in
the ones place. Label the place values instead of saying digits.
HomeCounting with Word Numbers
Thinking Addition means "Join Together" and Subtraction means "Take Away"
Misapplying Addition and Subtraction Strategies to Multiplication and Division
Multiplying Two - Digit Factors by Two - Digit Factor
Understanding the Division Algorithm
Understanding Fractions
Adding and Subtracting Fractions
Representing, Ordering and Adding/Subtracting Decimals
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