Math challenge for my grade 5

Question

Myla bought a jar shaped having a length of 130 cm, a width of 70 cm, and a height of 110 cm. How much water is needed to fill the jar?

Answer 1

A box shaped jar, which has volume 130 cm * 70 cm * 110 cm = 1001000 cubic centimeters

1 meter = 100 cm

1 cubic meter = 1000000 cubic centimeters

Dividing that volume by the million , the volume in cubic meters is 1.001

Density = mass/volume, so Density * volume = mass

The density of water is 997 kg per cubic meter

So based on this volume, mass = density * volume = 997 kg per cubic meter * 1.001 cubic meters

= 997.997 kg

1 kg = 2.23 lb

so 997.997 kg * 2.23 lb/kg = 2225.53331 lb

1 gallon of water weights and 8 1/3 lb

2225.5331 lb divided by 8 and 1/3 lb =

267 gallons