@ryandougherty.bsky.social
I broke 15 into 10 and 5.
10 x 36 = 360 (Full circle)
5 x 36 = 180 (Half circle)
From watching the Olympics, I know a 1.5 rotation is called a 540, and 360 + 180 = 540
10 x 36 = 360 (Full circle)
5 x 36 = 180 (Half circle)
From watching the Olympics, I know a 1.5 rotation is called a 540, and 360 + 180 = 540
November 24, 2025 at 6:10 PM
I broke 15 into 10 and 5.
10 x 36 = 360 (Full circle)
5 x 36 = 180 (Half circle)
From watching the Olympics, I know a 1.5 rotation is called a 540, and 360 + 180 = 540
10 x 36 = 360 (Full circle)
5 x 36 = 180 (Half circle)
From watching the Olympics, I know a 1.5 rotation is called a 540, and 360 + 180 = 540
I started at 73.
Subtracted 3 to get 70.
Subtracted 30 to get 40.
Then subtracted 4 to get 36.
Breaking the 37 into more manageable numbers makes the subtraction easier for me.
Subtracted 3 to get 70.
Subtracted 30 to get 40.
Then subtracted 4 to get 36.
Breaking the 37 into more manageable numbers makes the subtraction easier for me.
November 17, 2025 at 4:32 PM
I started at 73.
Subtracted 3 to get 70.
Subtracted 30 to get 40.
Then subtracted 4 to get 36.
Breaking the 37 into more manageable numbers makes the subtraction easier for me.
Subtracted 3 to get 70.
Subtracted 30 to get 40.
Then subtracted 4 to get 36.
Breaking the 37 into more manageable numbers makes the subtraction easier for me.
I broke the 27 into 25 + 2. Seeing the 25 made me think of money.
8 X 25 = 8 quarters = $2.00
8 X 2 = 16 pennies = $0.16
$2.00 + $0.16 = $2.16
8 x 27 = 216
8 X 25 = 8 quarters = $2.00
8 X 2 = 16 pennies = $0.16
$2.00 + $0.16 = $2.16
8 x 27 = 216
November 10, 2025 at 3:39 PM
I broke the 27 into 25 + 2. Seeing the 25 made me think of money.
8 X 25 = 8 quarters = $2.00
8 X 2 = 16 pennies = $0.16
$2.00 + $0.16 = $2.16
8 x 27 = 216
8 X 25 = 8 quarters = $2.00
8 X 2 = 16 pennies = $0.16
$2.00 + $0.16 = $2.16
8 x 27 = 216
Flip the problem - What is 50% of 30?
Half of a number is easier for me. Half of 30 is 15.
I used the model on the right, but then double checked with the original one on the left.
Half of a number is easier for me. Half of 30 is 15.
I used the model on the right, but then double checked with the original one on the left.
November 3, 2025 at 3:52 PM
Flip the problem - What is 50% of 30?
Half of a number is easier for me. Half of 30 is 15.
I used the model on the right, but then double checked with the original one on the left.
Half of a number is easier for me. Half of 30 is 15.
I used the model on the right, but then double checked with the original one on the left.
2 ways.
1st - I was born in 1974, so they are 2 years younger than me. I'm 51, they are or will be 49.
2nd - On a number line. 2025 - 50 is 1975. I subtracted 1 too many. Add the -1 back and I also get 49.
(number line not to scale)
1st - I was born in 1974, so they are 2 years younger than me. I'm 51, they are or will be 49.
2nd - On a number line. 2025 - 50 is 1975. I subtracted 1 too many. Add the -1 back and I also get 49.
(number line not to scale)
October 27, 2025 at 3:54 PM
2 ways.
1st - I was born in 1974, so they are 2 years younger than me. I'm 51, they are or will be 49.
2nd - On a number line. 2025 - 50 is 1975. I subtracted 1 too many. Add the -1 back and I also get 49.
(number line not to scale)
1st - I was born in 1974, so they are 2 years younger than me. I'm 51, they are or will be 49.
2nd - On a number line. 2025 - 50 is 1975. I subtracted 1 too many. Add the -1 back and I also get 49.
(number line not to scale)
I added all the tens first to get 40. I was left with 3+5+7+9.
3+7= 10 (add that to my 10's group to now have 50)
5+9= 14 (another ten to get 60)
60 + 4 = 64
3+7= 10 (add that to my 10's group to now have 50)
5+9= 14 (another ten to get 60)
60 + 4 = 64
October 20, 2025 at 4:11 PM
I added all the tens first to get 40. I was left with 3+5+7+9.
3+7= 10 (add that to my 10's group to now have 50)
5+9= 14 (another ten to get 60)
60 + 4 = 64
3+7= 10 (add that to my 10's group to now have 50)
5+9= 14 (another ten to get 60)
60 + 4 = 64
First thought - it is just less than 20 if I didn't need to be exact.
Second thought - reverse the numbers - 40% of 45.
10% of 45 is 4.5. I need four of those.
4.5 + 4.5 + 4.5 + 4.5 = 18.
(Solved this as 9 + 9 or (4x4) + 2)
Second thought - reverse the numbers - 40% of 45.
10% of 45 is 4.5. I need four of those.
4.5 + 4.5 + 4.5 + 4.5 = 18.
(Solved this as 9 + 9 or (4x4) + 2)
October 6, 2025 at 4:23 PM
First thought - it is just less than 20 if I didn't need to be exact.
Second thought - reverse the numbers - 40% of 45.
10% of 45 is 4.5. I need four of those.
4.5 + 4.5 + 4.5 + 4.5 = 18.
(Solved this as 9 + 9 or (4x4) + 2)
Second thought - reverse the numbers - 40% of 45.
10% of 45 is 4.5. I need four of those.
4.5 + 4.5 + 4.5 + 4.5 = 18.
(Solved this as 9 + 9 or (4x4) + 2)
I made all the numbers 20. 20 x 5 = 100
Then, subtracted 4, 3, 2, and 1.
100 - 10 = 90
Then, subtracted 4, 3, 2, and 1.
100 - 10 = 90
September 29, 2025 at 3:35 PM
I made all the numbers 20. 20 x 5 = 100
Then, subtracted 4, 3, 2, and 1.
100 - 10 = 90
Then, subtracted 4, 3, 2, and 1.
100 - 10 = 90
A second way (not my preferred, but a different way to solve it.)
September 22, 2025 at 5:43 PM
A second way (not my preferred, but a different way to solve it.)
First way I saw it was --
6+9 = 15
7+8 = 15
15+15 = 30
6+9 = 15
7+8 = 15
15+15 = 30
September 22, 2025 at 5:42 PM
First way I saw it was --
6+9 = 15
7+8 = 15
15+15 = 30
6+9 = 15
7+8 = 15
15+15 = 30
I subtracted 50 instead of 45. I knew I subtracted too much, so I added 5 back.
112-45 = 112-50+5
67
112-45 = 112-50+5
67
September 15, 2025 at 3:41 PM
I subtracted 50 instead of 45. I knew I subtracted too much, so I added 5 back.
112-45 = 112-50+5
67
112-45 = 112-50+5
67
Knowing 7.5% x 250 is the same as 250% of 7.5, I am going to find double and half of 7.5. I know 100% of 7.5 = 7.5.
Double - 200% of 7.5 = 15
Half - 50% of 7.5 = 3.75
Using those numbers to find 250% -
15+ 3.75 = 18.75
Double - 200% of 7.5 = 15
Half - 50% of 7.5 = 3.75
Using those numbers to find 250% -
15+ 3.75 = 18.75
September 8, 2025 at 4:42 PM
Knowing 7.5% x 250 is the same as 250% of 7.5, I am going to find double and half of 7.5. I know 100% of 7.5 = 7.5.
Double - 200% of 7.5 = 15
Half - 50% of 7.5 = 3.75
Using those numbers to find 250% -
15+ 3.75 = 18.75
Double - 200% of 7.5 = 15
Half - 50% of 7.5 = 3.75
Using those numbers to find 250% -
15+ 3.75 = 18.75
Three 7's is 21
Two 5's are 10
21 + 10 = 31
Two 5's are 10
21 + 10 = 31
August 25, 2025 at 3:53 PM
Three 7's is 21
Two 5's are 10
21 + 10 = 31
Two 5's are 10
21 + 10 = 31
Start by rearranging the problem into 3 smaller problems.
2x5=10
2x5=10
3x3=9
Use those products again
10x10= 100
10x9=900
2x5=10
2x5=10
3x3=9
Use those products again
10x10= 100
10x9=900
August 18, 2025 at 4:32 PM
Start by rearranging the problem into 3 smaller problems.
2x5=10
2x5=10
3x3=9
Use those products again
10x10= 100
10x9=900
2x5=10
2x5=10
3x3=9
Use those products again
10x10= 100
10x9=900
I divided the entire problem by 2 to get 500 ÷ 4.
I saw it as $5.00 ÷ 4. Each area gets 1 dollar, then each area gets 0.25¢.
1000 ÷ 8 = 125
I saw it as $5.00 ÷ 4. Each area gets 1 dollar, then each area gets 0.25¢.
1000 ÷ 8 = 125
August 11, 2025 at 5:30 PM
I divided the entire problem by 2 to get 500 ÷ 4.
I saw it as $5.00 ÷ 4. Each area gets 1 dollar, then each area gets 0.25¢.
1000 ÷ 8 = 125
I saw it as $5.00 ÷ 4. Each area gets 1 dollar, then each area gets 0.25¢.
1000 ÷ 8 = 125
If 20 = $36, then 10 = $18
If 10 = $18, then I know 5 = $9 and 1 = $1.80
Knowing all that, I can use those numbers to find the cost of 6.
$9.00 + $1.80 = $10.80
If 10 = $18, then I know 5 = $9 and 1 = $1.80
Knowing all that, I can use those numbers to find the cost of 6.
$9.00 + $1.80 = $10.80
August 4, 2025 at 3:15 PM
If 20 = $36, then 10 = $18
If 10 = $18, then I know 5 = $9 and 1 = $1.80
Knowing all that, I can use those numbers to find the cost of 6.
$9.00 + $1.80 = $10.80
If 10 = $18, then I know 5 = $9 and 1 = $1.80
Knowing all that, I can use those numbers to find the cost of 6.
$9.00 + $1.80 = $10.80
625 - 75 = 550 (thinking about money and subtracting quarters helped.)
I know I subtracted 3 more than I needed to, so I can add that back.
550 + 3 = 553
I know I subtracted 3 more than I needed to, so I can add that back.
550 + 3 = 553
July 28, 2025 at 4:14 PM
625 - 75 = 550 (thinking about money and subtracting quarters helped.)
I know I subtracted 3 more than I needed to, so I can add that back.
550 + 3 = 553
I know I subtracted 3 more than I needed to, so I can add that back.
550 + 3 = 553
If 6 stickers cost $4.50, how much do 2 stickers cost?
$4.50 ÷ 3 = $1.50
2 stickers cost $1.50, and we need 10 times that amount.
2 X 10 = 20
$1.50 X 10 = $15.00
$4.50 ÷ 3 = $1.50
2 stickers cost $1.50, and we need 10 times that amount.
2 X 10 = 20
$1.50 X 10 = $15.00
July 21, 2025 at 3:55 PM
If 6 stickers cost $4.50, how much do 2 stickers cost?
$4.50 ÷ 3 = $1.50
2 stickers cost $1.50, and we need 10 times that amount.
2 X 10 = 20
$1.50 X 10 = $15.00
$4.50 ÷ 3 = $1.50
2 stickers cost $1.50, and we need 10 times that amount.
2 X 10 = 20
$1.50 X 10 = $15.00
14/40 = 7/20
7/20 = 3.5/10
3.5/10 = 35/100
35/100 = 35%
7/20 = 3.5/10
3.5/10 = 35/100
35/100 = 35%
July 21, 2025 at 3:38 PM
14/40 = 7/20
7/20 = 3.5/10
3.5/10 = 35/100
35/100 = 35%
7/20 = 3.5/10
3.5/10 = 35/100
35/100 = 35%
Like your subtraction post the other day. Change the numbers to make them easier.
89 + 17 becomes 90 + 16
90 + 10 = 100
100 + 6 = 106
89 + 17 = 106
89 + 17 becomes 90 + 16
90 + 10 = 100
100 + 6 = 106
89 + 17 = 106
July 7, 2025 at 4:46 PM
Like your subtraction post the other day. Change the numbers to make them easier.
89 + 17 becomes 90 + 16
90 + 10 = 100
100 + 6 = 106
89 + 17 = 106
89 + 17 becomes 90 + 16
90 + 10 = 100
100 + 6 = 106
89 + 17 = 106
Change the problem to 75% of 60.
60 ÷ 4 = 15
60 - 15 = 45
60 ÷ 4 = 15
60 - 15 = 45
June 30, 2025 at 4:15 PM
Change the problem to 75% of 60.
60 ÷ 4 = 15
60 - 15 = 45
60 ÷ 4 = 15
60 - 15 = 45
Change the problem to 20 x 8. 20 x 8 = 160
I know I have 2 groups of 8 more than I need. 2 x 8 = 16
Subtract the extra. 160 - 16 = 144
I know I have 2 groups of 8 more than I need. 2 x 8 = 16
Subtract the extra. 160 - 16 = 144
June 23, 2025 at 4:49 PM
Change the problem to 20 x 8. 20 x 8 = 160
I know I have 2 groups of 8 more than I need. 2 x 8 = 16
Subtract the extra. 160 - 16 = 144
I know I have 2 groups of 8 more than I need. 2 x 8 = 16
Subtract the extra. 160 - 16 = 144
I multiplied 9 x 40 to get 360. Then I moved the decimal to what makes the most sense. I could have chosen:
.360
3.60
36.0
360.0
Knowing that 10% of 40 is 4, the only option that makes sense is 3.6.
.360
3.60
36.0
360.0
Knowing that 10% of 40 is 4, the only option that makes sense is 3.6.
June 16, 2025 at 4:28 PM
I multiplied 9 x 40 to get 360. Then I moved the decimal to what makes the most sense. I could have chosen:
.360
3.60
36.0
360.0
Knowing that 10% of 40 is 4, the only option that makes sense is 3.6.
.360
3.60
36.0
360.0
Knowing that 10% of 40 is 4, the only option that makes sense is 3.6.
Like finding the amount of a 20% tip, I found 10% and doubled it.
10% = $2.40
20% = $4.80
Instead of adding (like a tip), I subtracted for the sale price.
10% = $2.40
20% = $4.80
Instead of adding (like a tip), I subtracted for the sale price.
June 9, 2025 at 5:30 PM
Like finding the amount of a 20% tip, I found 10% and doubled it.
10% = $2.40
20% = $4.80
Instead of adding (like a tip), I subtracted for the sale price.
10% = $2.40
20% = $4.80
Instead of adding (like a tip), I subtracted for the sale price.
I had to write all the number out. When I did, I saw I could make groups of 30. (0+30, 3+27, 6+24, 9+21, 12+18) with 15 remaining.
5 groups of 30 is 150.
150 + 15 = 165
5 groups of 30 is 150.
150 + 15 = 165
June 2, 2025 at 3:36 PM
I had to write all the number out. When I did, I saw I could make groups of 30. (0+30, 3+27, 6+24, 9+21, 12+18) with 15 remaining.
5 groups of 30 is 150.
150 + 15 = 165
5 groups of 30 is 150.
150 + 15 = 165