Word problem strategies Working Backwards Working backwards In
Word problem strategies Working Backwards
Working backwards In this strategy students find the solution to a problem by starting with the answer and using inverse operations to undo the steps stated in the problem. e. g. , a + b = c : c - a = b
Question: Jack walked from Santa Clara to Palo Alto. It took 1 hour 25 minutes to walk from Santa Clara to Los Altos. Then it took 25 minutes to walk from Los Altos to Palo Alto. He arrived in Palo Alto at 2: 45 P. M. At what time did he leave Santa Clara?
Step 1 - Understand l What do you need to find? You need to find what the time was when Jack left Santa Clara, the start time. They have given you the end time and elapsed time.
Step 2: Plan l How can you solve the problem? You can work backwards from the time Jack reached Palo Alto. Subtract the time it took to walk from Los Altos to Palo Alto. Then subtract the time it took to walk from Santa Clara to Los Altos.
Step 3: Solve l Start at 2: 45. This is the time Jack reached Palo Alto. l Subtract 25 minutes. This is the time it took to get from Los Altos to Palo Alto. Time is: 2: 20 P. M. l l Subtract: 1 hour 25 minutes. This is the time it took to get from Santa Clara to Los Altos. . l Jack left Santa Clara at 12: 55 P. M.
Guided Practice question At the Art Fair, you purchased a set of acrylic paints for $7 and 2 identical paintbrushes. You spent a total of $19. What was the cost of 1 paintbrush?
Step 1 - Understand l What do you need to find? You need to find out how much 1 paintbrush costs. They have given you the sum of all of the supplies.
Step 2: Plan l How can you solve the problem? You can work backwards from the total cost taking away the cost of the paints. That will leave you with how much 2 brushes cost, then divide by 2.
Step 3: Solve l Start at $19. This is the total cost of the art supplies. l Subtract $7 dollars. This is the cost of the acrylic paints. l The remaining total is: $12. This is the cost of 2 paint brushes. l Divide: $12 in two. This is the cost of 1 paint brush. l 1 paint brush costs $6.
At the Art Fair, you purchased a set of acrylic paints for $6 and 2 identical paintbrushes. You spent a total of $14. What was the cost of 1 paintbrush? A. B. C. D. $8 $6 $5 $4
Independent Practice questions On a clean sheet of paper solve these practice questions using this strategy. I should see you using the opposite operation and any other skill you need to work backwards.
On the way home from school Thomas lost 5 marbles, then he gave 3 to Max. When he got home, he had 6 marbles. How many marbles did he have when he let school A. B. C. D. 16 14 12 8
Tina needs to arrive at school at 7: 35 a. m. It takes her 10 minutes to walk to school and 45 minutes to get ready in the morning. What is the latest time she can get up in the morning so that she arrives at school on time? 7: 00 B. 6: 45 C. 6: 40 [Default] [MCD. Any]6: 25 [MC All] A.
Lee takes 15 minutes to shower and dress, 10 minutes to eat breakfast, and 20 minutes to do his chores and walk to his bus stop. If the school bus picks him up at 7: 40 a. m. what is the latest time Lee can get up in the morning? 6: 45 B. 6: 50 C. 6: 55 [Default] [MCD. Any]7: 00 [MC All] A.
A box has red and blue marbles. You put in 4 red marbles. You take out 1 blue marble. There are 8 at the end, and the probability of selecting blue was 3/8. How many red marbles were in the box? A. B. C. D. 0 1 2 3 [Default] [MC Any] [MC All]
Jim divides a bag of candy into 5 equal piles. He gives 4 piles to friends and keeps one for himself. He eats 7 pieces of candy and has 5 pieces remaining. How many pieces of candy were in the whole bag? A. B. C. D. 60 48 36 24 [Default] [MC Any] [MC All]
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