Hey there! 
• One digit will be in the ONES place
• Two digits will be in the TENS place
• Three digits will be in the HUNDREDS place
• Four digits will be in the THOUSANDS place
And much much more! 
35 = 3 tens + 5 ones 
16 = 1 ten 6 ones 
“3 tens + 5 ones + 1 ten + 6 ones”
Now we can answer your question 
3 would be in the TENS place 
5 would be in the ONES place
+
1 would be in the TENS place 
6 would be in the ONES place 
35 + 16
= 30 + 05 + 10 + 06
= 35 + 16 (yes again)
= 50 + 01 (whereas 5 is in the TENS place & 0 is in the ONES place and 0 is in the TENS place and ONES place) 
= 51
Therefore, your answer should be: 51 or 5 tens + 1 one 
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)