• • • • • • # Nov/Dec 2019

• # Oct/Nov 2019

• # Math Strategies (to go with Oct/Nov News 2019)

Plus Zero: Add 0 to a number and the number stays the same. 3 + 0 = 3

Count On +1, +2, +3: Count up when adding on small numbers, such as 1, 2, or 3.

Turn Around: Add numbers in any order and the total(sum) stays the same. 4 + 2 = 6, 2 + 4 = 6

Doubles: Add the number to itself and that number doubles.  4 + 4 = 8  (picture clues)

Near Doubles: Double the smaller number and add one more. 4 + 5 = 4 + 4 + 1

Tens Partners: There are six sets of number pairs that make 10.  10 + 0, 9 + 1, 8 + 2, 7 + 3, 6 + 4, 5 + 5

Fast 10s: When 10 is added to a number, the tens-place digit increases by one. 9 + 10 = 19

Fast 9s:  To add 9 to a number, add 10 instead and jump back one. See 6 + 9. Think 6 + 10 – 1

Make a Ten:  For 8 + 6, I separate the 6 into 2 and 4. I add 8 + 2 to make 10, and then add the 4 on to get 14. Ultimately, students are breaking numbers into easier to add parts.

Use a Fact I Know: Same idea as above where students break numbers apart to add chunks easier. I know 8 + 3 = 11, so 8 + 5 = 13 (2 more than 11)

Multiplication Fact Strategies:

The 0’s – anything times 0 is 0; ex. 6x0=0, 0x21=0, 0x1000=0

The 1’s – anything times 1 is itself; ex. 3x1=3, 900x1=900

The 2’s – think of the addition doubles; ex. For 2x, think 6+ 6 (2 groups of 6)

The 5’s – skip-count by 5’s (5, 10, 15, 20, 25...)  ex. For 5x4, skip-count by 5’s 4 times (5, 10, 15, 20)

The 10’s – add a zero to the end of the number being multiplied by 10; ex. For 4x10, add a 0 to the 4 to make 40; Students can also skip-count by 10’s

The 9’s –First, look at the equation and find the factor that is not the 9 (for example, in the equation 9x4, look at the 4). Next, subtract 1 from that factor (in this case, 4-1=3). Place this number in the tens place of the answer (in this case, the 3 will be in the tens place). Ask yourself what you can add to the 3 to make 9 (the two numbers in the answer will always equal 9). In this case, 3+6=9, so the second number in the answer is a 6. In this equation, the answer is 36. This may seem confusing at first, but try it a couple times and see how it works.

(Students will also be taught the hand trick for 9s.)

The 4’s – think double-double; ex. For 4x6, first double the 6 to make 12, and then double the 12 to make 24.

The 3’s – the double plus one more group; ex. For 3x4, double the 4 to make 8, and then add one more group of 4 to make 12. For 6x3, double the 6 to make 12 and then add one more group of 6 to make 18.

The 6’s, 7’s and 8’s – build on known facts and use what you already know to solve.  ex. To solve 6x6, use a fact that you already know, such as 6x5=30, then add one more group of 6. To solve 7x8, think of a fact that you already know, such as 7x9=63, and subtract a group of 7 to make 56.

Kids can also use the Distributive Property and break one of the numbers apart into two digits that are easier to multiply. 7 x 8 = (5 x 8) + (2 x 8) = 40 + 16 = 56. This is a great strategy for solving unknown facts using facts a student already knows to find the answer easier.

• # Sept/Oct 2019

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