I can add and subtract decimals by lining up the place values and the decimal points.Puedo sumar y restar decimales alineando los valores posicionales y los puntos decimales.
MissionMisión · Summit TrailSendero a la cumbre · night shiftturno de noche
Every checkpoint gets you higher.Cada punto de control te lleva más alto.
Night falls on Summit Trail and the fog rolls in. Your trail log has to be exact, because one misplaced decimal point could send a group in the wrong direction.
Cae la noche en Summit Trail y llega la niebla. Tu registro del sendero tiene que ser exacto, porque un punto decimal mal colocado podría mandar a un grupo en la dirección equivocada.
Word bankBanco de palabras 5 words5 palabrasdecimal, place value, tenths, …decimal, valor posicional, décimas, …
- decimaldecimal
- A number with a point that shows a part less than one whole.Un número con un punto que muestra una parte menor que un entero.
- 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.
- tenthsdécimas
- The first place after the decimal point. It shows parts out of 10.El primer lugar después del punto decimal. Muestra partes de 10.
- hundredthscentésimas
- The second place after the decimal point. It shows parts out of 100.El segundo lugar después del punto decimal. Muestra partes de 100.
- annex zerosagregar ceros
- Write extra zeros at the right end of a decimal so the places line up. The value does not change.Escribir ceros extra al final de un decimal para que los lugares se alineen. El valor no cambia.
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 Tasha's Mistake
- A runner's lap times are 2.45 minutes, 2.6 minutes, and 2.38 minutes. Her personal record is 7.5 minutes total. Did she beat her record? Show all your work with decimal alignment and explain.
- A hiking club logged three days on a 50 km trail, shown in the table. How many kilometers are left to hike?
- A backpack may weigh at most 14.5 kg. Tent: 3.85 kg. Sleeping bag: 1.9 kg. Water: 2.5 kg. Food: 4.65 kg. Does the pack fit the limit, and by how much?
- It fits, with 2.4 kg to spare.
- It is over the limit by 1.6 kg.
- It fits, with 5.56 kg to spare.
- It fits, with 1.6 kg to spare.
- Fill in the elevation after each leg of Summit Trail. A plus sign means the hikers climb, and a minus sign means they go down.
- Two routes lead to the lookout. Route A has legs of 3.4 km, 2.85 km, and 4.7 km. Route B has legs of 5.25 km and 4.9 km. Which route is shorter, and by how much?
- Route A is shorter, by 0.8 km.
- Route B is shorter, by 0.8 km.
- Route B is shorter, at 10.15 km.
- Route A is shorter, by 2.08 km.
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.
- The trail ranger checks six sums and differences. Sort each one by whether the exact answer is a whole number.
- Make up your own problem with two decimals: a first number of 10 or more with only tenths (like 24.6) and a second number below 10 with hundredths (like 7.85). Annex a zero, line up the decimal points, and find the sum and the difference on paper. Then check both in the model and with an estimate.
- 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 trail guide added two water amounts. One step goes wrong. Tap the first step that is wrong.
- A hiker figured out how far is left on a 30 km trail. One step goes wrong. Tap the first step that is wrong.
- A camper wanted to give a number two decimal places before subtracting. One step goes wrong. Tap the first step that is wrong.
- Ana and Ben added 0.7 + 0.35 for the trail log. Ana wrote 0.7 as 0.70 and got 1.05. Ben added 7 + 35 and wrote 0.42. Who is right?
- Only Ana: 0.7 is 70 hundredths, and 70 + 35 = 105 hundredths, which is 1.05.
- Only Ben: 7 + 35 = 42, so the sum is 0.42.
- Both are right, because 1.05 and 0.42 are two ways to write the sum.
- Neither: the sum is 0.105.
- What is the best next move?
- Write 20 as 20.00 and subtract 11.35 from it.
- Add 20 + 11.35 to find what is left.
- Say 11.35 m is the ribbon left.
- Put 20 above 11.35 with the last digits in line, then subtract.
- 1 fresh problem with new numbers each time (interactive only).
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.
- Three sections of a ridge trail measure 4.8 km, 6.35 km, and 2.075 km. What is the total length of the three sections?
- A water tank at base camp holds 60 liters. A group draws out 24.08 liters. How many liters are left?
- A group of hikers needs 25 liters of water for the climb. Mia carries 8.75 liters and Noor carries 6.5 liters. How many more liters does the group need?
- A guide wants to subtract 1.45 from 3.2. Why is it correct to write 3.2 as 3.20 first?
- The zero makes the number bigger, so the subtraction is easier.
- Every decimal must have exactly two digits after the point.
- A trailing zero adds a place, not value.
- The zero moves the decimal point one place to the right.
- A hiker walked three legs: 3.75 km, 2.8 km, and 4.15 km. How many kilometers longer is the longest leg than the shortest leg?
- Write your own Summit Trail problem that needs one addition and one subtraction of decimals with different numbers of decimal places. Solve it, show how you lined up the places, and check your answer with an estimate.