For 952: just find the moles first using mass/molar mass then take 85 per cent of that :)) Let me know if this technique works
for 880: find the difference between the two readings which gives the volume of the NaOH used. then use the equation m1v1=m2v2 using the values given to find the concentration. Then use moles=concentration x volume converted into litres to find the molarity!
Hope this helps! Let me know if you need the calculation done:)