Questions

 #include<stdio.h>
int main(){
  int r,i,j,k;
  printf("Enter the number range: ");
  scanf("%d",&r);
  for(i=1;i<=r;i++){
      for(j=1;j<=10;j++)
           printf("%d*%d=%d ",i,j,i*j);
      printf("\n");
  }
  return 0;
}

Sample Output:
Enter the number range: 5

1*1=1 1*2=2 1*3=3 1*4=4 1*5=5 1*6=6 1*7=7 1*8=8 1*9=9 1*10=10
2*1=2 2*2=4 2*3=6 2*4=8 2*5=10 2*6=12 2*7=14 2*8=16 2*9=18 2*10=20
3*1=3 3*2=6 3*3=9 3*4=12 3*5=15 3*6=18 3*7=21 3*8=24 3*9=27 3*10=30
4*1=4 4*2=8 4*3=12 4*4=16 4*5=20 4*6=24 4*7=28 4*8=32 4*9=36 4*10=40
5*1=5 5*2=10 5*3=15 5*4=20 5*5=25 5*6=30 5*7=35 5*8=40 5*9=45 5*10=50

23 hrs, 56 minutes and 4.9 seconds

Proxima Centauri is the nearest star to the Earth.

Wavelength of a wave can be measured with the distance between two nearest crest and crest or nearest troughs. It is measured as armstrong units.

True, poorly controlled stress and anger can lead to heart attacks and strokes.

Potassium bicarbonate (also known as potassium hydrogen carbonate or potassium acid carbonate) is the inorganic compound with the chemical formula KHCO3. It is a white solid

Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder.

LiHCO3 is found in solution form while rest alkali metals hydrogen carbonates are solid due to the anomalous properties of Li and its diagonal relationship with the Mg.