I can multiply decimals and place the decimal point correctly in the product.Puedo multiplicar decimales y colocar correctamente el punto decimal en el producto.
MissionMisión · Harbor WorksPuerto de trabajo · night shiftturno de noche
Keep the port running.Mantén el puerto en marcha.
A storm has delayed the fleet, and the harbor is full of ships waiting to be billed. One misplaced decimal point could overcharge a crew by hundreds of dollars, so check every product with an estimate.
Una tormenta retrasó a la flota y el puerto está lleno de barcos esperando su factura. Un punto decimal mal colocado podría cobrarle de más a una tripulación cientos de dólares, así que comprueba cada producto con una estimación.
Word bankBanco de palabras 5 words5 palabrasproduct, decimal point, decimal places, …producto, punto decimal, cifras decimales, …
- productproducto
- The answer when you multiply.La respuesta cuando multiplicas.
- decimal pointpunto decimal
- The dot that separates the whole-number part from the part after it.El punto que separa la parte entera de la parte que sigue.
- decimal placescifras decimales
- How many digits come after the decimal point.Cuántos dígitos hay después del punto decimal.
- estimateestimar
- Find an answer that is close by rounding first. It helps check the exact answer.Hallar una respuesta cercana redondeando primero. Ayuda a comprobar la respuesta exacta.
- place valuevalor posicional
- What a digit is worth because of where it sits in the number.Lo que vale un dígito por el lugar que ocupa en el número.
Stage 1 of 5Etapa 1 de 5
Start StrongEmpieza fuerte
Each rung is harder than the last, and the numbers change every time.
Cada peldaño es más difícil que el anterior y los números cambian cada vez.
- 6 fresh problems with new numbers each time (interactive only).
Stage 2 of 5Etapa 2 de 5
Stretch Your ThinkingAmplía tu pensamiento
Plan, solve, then check that your answer makes sense.
Planea, resuelve y revisa que tu respuesta tenga sentido.
- Find Kai's Mistake
- A driver buys 9.5 gallons of gas at $3.40 per gallon. Show how to find the total cost. Use estimation to check if your answer is reasonable.
- A harbor crew orders rope. The price list is shown in the table. What is the total cost of the order, with delivery included?
- Tug A burns 4.8 liters of fuel each hour and runs for 3.5 hours. Tug B burns 5.25 liters each hour and runs for 3 hours. How many more liters does Tug A burn than Tug B?
- Fill in each charge in dollars. Charge = amount × rate.
- A harbor clerk needs the cost of 7.5 m of cable at $0.46 per meter. Estimate first, then choose the exact cost.
- $0.345, because $0.46 is less than a dollar.
- $34.50, because 7.5 × 4.6 is about 35.
- $3.45: 0.5 × 7.5 ≈ $3.75.
- $345, because 7.5 × 46 = 345.
Stage 3 of 5Etapa 3 de 5
InvestigateInvestiga
Use the model to test an idea. Then check it.
Usa el modelo para probar una idea. Luego compruébala.
- A harbor clerk places the decimal point in six products. Before any zeros are dropped, how many decimal places does each product need? Sort each multiplication.
- Create a receipt with two products. Give each a price and a quantity, multiply to find each subtotal, add them, and subtract from $50.00. Include an estimate and one decimal-point mistake a shopper should avoid.
- 4 fresh problems with new numbers each time (interactive only).
Stage 4 of 5Etapa 4 de 5
Find and FixEncuentra y corrige
Somebody made a mistake. Find the step and fix it.
Alguien cometió un error. Encuentra el paso y corrígelo.
- A clerk priced a piece of chain. One step goes wrong. Tap the first step that is wrong.
- A worker found how much sealant a hull patch needs. One step goes wrong. Tap the first step that is wrong.
- A crane operator figured out the weight of four loads. One step goes wrong. Tap the first step that is wrong.
- A boat stays at the dock for 0.5 hour, and the harbor charges $12 per hour. Ana says the bill is $6. Ben says the bill must be more than $12, because multiplying always makes numbers bigger. Who is right?
- Ana: half an hour costs half of $12.
- Ben: multiplying always gives a number greater than both factors.
- Neither: the bill is $60, because 12 × 5 = 60.
- Neither: the bill is $0.60, because 12 × 5 = 60 and the point moves two places.
- What is the best next move?
- Multiply 54 × 275 again to recheck the digits.
- Trust $148.50, because 54 × 275 = 14,850 is right.
- Estimate with friendly numbers; check against $148.50.
Stage 5 of 5Etapa 5 de 5
Prove Your UnderstandingDemuestra tu comprensión
Say how sure you are, solve, then create a problem of your own.
Di qué tan seguro estás, resuelve y luego crea un problema tuyo.
- A reflective stripe on a buoy is 0.3 m long and 0.02 m wide. What is the area of the stripe in square meters?
- The floor of a cargo hold is 6.8 m long and 4.5 m wide. What is the area of the floor in square meters?
- A clerk knows that 24 × 35 = 840. The harbor needs 2.4 m of shrink-wrap at $0.35 per meter. What is the cost?
- $0.084
- $0.84
- $8.40
- $84
- Which statement about the product 0.8 × 0.9 is true?
- The product is greater than both factors, because multiplying always makes numbers bigger.
- The product is 7.2, because 8 × 9 = 72 and the point goes after the 7.
- The product is 0.72, which is less than both factors.
- The product is 0.072, because there are 3 decimal places in all.
- A ferry burns 12.5 liters of fuel each hour. Fuel costs $1.15 per liter. What is the fuel cost of a 3.6-hour trip, in dollars?
- Write your own Harbor Works problem that multiplies two decimals with different numbers of decimal places. Solve it, explain where you put the decimal point and why, and use an estimate to show your answer is reasonable.
- 1 fresh problem with new numbers each time (interactive only).