The weight of an object is the product of its mass, m, and the acceleration of gravity, g (where g=9.8 m/s2). If an object’s mass is m=10. kg, what is its weight?
You just told us that mass is 10 kg, acceleration of gravity is 9.8 m/s², and weight is their product, so we don't need to be too awfully clever to calculate the weight. It's (10) x (9.8) = 98 newtons.